Service Manual2006 Nubira-Lacetti Diagnostic Trouble Code (DTC) P0171

Nubira-Lacetti

Diagnostic Trouble Code (DTC) P0171

Fuel Trim System Too Lean

System Description

If the adaptation value threshold is permanently exceeded, the deviation of the adaptive terms enables to detect a slow default coming out. Two time counters (one for the rich side and another one for the lean side) are increased while the lambda controller exceeds the adaptation thresholds. As soon as one of the time counters reaches its maximum value, the error is detected.

The aim of this test is to simulate a failure that would result in exceeding the adaptive terms. Two kinds of failure must be created.

A lean side deviation: P0171
A rich side deviation : P0172

It is thus necessary to determine, for each kind of failure, the limit good and the limit bad. For a given failure, measure the emission threshold until the legal emission thresholds are exceeded.

Note that the problem is due to the emission thresholds required, it is not simple to disturb the system so that the emission thresholds will be exceeded. The tuning has been made thanks to a dedicated calibration but, as such a procedure is not permitted by the regulation, it is necessary to create some material malfunction (fuel pressure regulator, fuel injector, air leakage...).

Conditions for Running the DTC

Vehicle is in closed loop condition.
Engine is running.
EVAP canister and fuel system operate normally.
No errors in ECT, IAT, MAP, CMP, CKP, or TP sensor.
Engine Coolant Temperature is higher than 20°C (68°F).

Conditions for Setting the DTC

(1.4 DOHC)

The average of short term fuel trim values plus adaptive fuel trim is higher than 33% during 330 seconds out of 550 second test period.

(1.6 DOHC)

The average of short term fuel trim values plus adaptive fuel trim is higher than 33% during 250 seconds out of 600 second test period for M/T.
The average of short term fuel trim values plus adaptive fuel trim is higher than 33% during 400 seconds out of 750 second test period for A/T.

Action Taken When the DTC Sets

The Malfunction Indicator Lamp (MIL) will illuminate.
The ECM will record operating conditions at the time the diagnostic fail. This information will be stored in the Freeze Frame and Failure Records buffers.
A history DTC is stored.

Conditions for Clearing the MIL/DTC

The MIL will turn off at the end of three consecutive validation cycles in which the diagnostic runs without a fault.
A history DTC will clear after 40 warm up cycles without a fault.
DTC(s) can be cleared by using the scan tool.

Diagnostic Aids

Important : After repairs, use the scan tool Fuel Trim Reset function to reset the long-term fuel trim to 128 (0%).

Fuel pressure - The system will be lean if the pressure is too low. It may be necessary to monitor fuel pressure while driving the vehicle at various road speeds and/or loads to confirm.
Map sensor - An output that causes the ECM to sense a lower than normal manifold pressure (high vacuum) can cause the system to go lean. Disconnecting the MAP sensor will allow the ECM to substitute a fixed (default) value for the MAP sensor. If the lean condition is gone when the sensor is disconnected, substitute a known good sensor and recheck.
Fuel contamination - Water, in even small amounts, near the in-tank fuel pump inlet can be delivered to the injector. The water causes a lean exhaust and can set DTC P0171.

Check for poor oxygen sensor or MAP sensor connection at the ECM. Inspect the harness connectors for the following conditions:

Backed-out terminals
Improper mating
Broken locks
Improperly formed
Damaged terminals
Poor terminal-to-wire connection

Inspect the wiring harness for damage. If the harness appears to be OK, observe the HO2S display on the scan tool while moving the connectors and the wiring harness related to the engine harness. A change in the display will indicate the location of the fault.

DTC P0171 - Fuel Trim System Too Lean

Step	Action	Value(s)	Yes	No
1	Perform the Diagnostic System Check. Is the system check complete?	-	Go to Step 2	Go to "Diagnostic System Check"
2	Install the scan tool to the Data Link Connector (DLC). Turn the ignition ON. Are any component related Diagnostic Trouble Codes (DTCs) set?	-	Go to applicable DTC table	Go to Step 3
3	With the engine running, operate the vehicle until the LOOP STATUS indicates closed. Is the Long Term Fuel Trim value below the specified value?	27%	Go to Step 4	Go to Step 5
4	Turn the ignition switch ON, with the engine OFF. Review the Freeze Frame data and note the parameters. Operate the vehicle within the Freeze Frame conditions and Conditions for Setting The DTC as noted. Does the Long Term Fuel Trim value go below the specified value while operating under the specified conditions?	27%	Go to Step 15	Go to Step 5
5	Visually/physically check the following items: Vacuum hoses for splits, kinks and improper connections. Crankcase ventilation oil/air separator for proper installation. Exhaust system for corrosion, leaks, loose or missing hardware. Oxygen sensor is installed securely and the pigtail harness is not contacting exhaust manifold or engine. Fuel for excessive water, alcohol, or other contaminants. Engine Control Module (ECM) and sensor grounds are clean, tight, and in their proper locations. Do any of the above checks isolate a condition requiring repair?	-	Go to Step 7	Go to Step 6
6	Disconnect the Manifold Absolute Pressure (MAP) sensor electrical connector. Operate the vehicle in Closed Loop while monitoring the Long Term Fuel Trim value. Is the Long Term Fuel Trim value below the specified value?	27%	Go to Step 14	Go to Step 9
7	Repair the malfunction found in Step 5. Recheck the Long Term Fuel Trim value while operating the engine. Is the Long Term Fuel Trim value below the specified value?	27%	Go to Step 8	Go to Step 9
8	Lean condition is not present. Does a driveability problem exist?	-	Go to "Symptom Diagnosis"	Go to Step 16
9	Visually/physically inspect the following items for vacuum leaks: Intake manifold. Throttle body. Injector O-rings. Repair any leaks found as necessary. Is the repair complete?	-	Go to Step 16	Go to Step 16
10	Check the IAC valve or MTIA performance. Was the repair necessary and completed?	-	Go to Step 15	Go to Step 11
11	Check the fuel for excessive water, alcohol, or other contaminants and correct the contaminated fuel condition if present. Is the repair complete?	-	Go to Step 15	Go to Step 12
12	Connect a fuel pressure gauge to the fuel system. Turn the ignition OFF for at least 10 seconds. Turn the ignition ON, with the engine OFF. The fuel pump will run for approximately 2-3 seconds. It may be necessary to cycle the ignition switch ON more than once to obtain maximum fuel pressure. Note the fuel pressure with the fuel pump running. The pressure should be within the specified value. When the fuel pump stops, the pressure may vary slightly then hold steady. Is the fuel pressure steady and does the fuel pressure hold?	380~402 kPa (55~58 psi)	Go to Step 13	Go to "Fuel System Diagnosis"
13	Start and idle the engine at normal operating temperature. The fuel pressure noted in the above step should drop by the indicated value. Does the fuel pressure drop by the indicated value?	21~69 kPa (3~10 psi)	Go to "Fuel Injector Balance Test"	Go to "Fuel System Diagnosis"
14	Replace the MAP sensor. Is the action complete?	-	Go to Step 15	-
15	Using the scan tool, clear the Diagnostic Trouble Codes (DTCs). Start the engine and idle at normal operating temperature. Operate the vehicle within the Conditions for setting this DTC as specified in the supporting text. Does the scan tool indicate that this diagnostic has run and passed?	-	Go to Step 16	Go to Step 2
16	Check if any additional DTCs are set. Are any DTCs displayed that have not been diagnosed?	-	Go to applicable DTC table	System OK

Diagnostic Trouble Code (DTC) P0172

Fuel Trim System Too Rich

System Description

A lean side deviation: P0171
A rich side deviation : P0172

It is thus necessary to determine, for each kind of failure, the limit good and the limit bad. For a given failure, measure the emission threshold until the legal emission thresholds are exceeded.Note that the problem is due to the emission thresholds required, it is not simple to disturb the system so that the emission thresholds will be exceeded. The tuning has been made thanks to a dedicated calibration but, as such a procedure is not permitted by the regulation, it is necessary to create some material malfunction (fuel pressure regulator, fuel injector, air leakage...).

Conditions for Running the DTC

Vehicle is in closed loop condition.
Engine is running.
EVAP canister and fuel system operate normally.
No errors in ECT, IAT, MAP, CMP, CKP, or TP sensor.
Engine Coolant Temperature is higher than 20°C (68°F).

Conditions for Setting the DTC

(1.4 DOHC)

The average of short term fuel trim values plus long term fuel trim is less than -28% during 302 seconds out of 550 second test period.

(1.6 DOHC)

The average of short term fuel trim values plus long term fuel trim is less than -30% during 200 seconds out of 600 second test period for M/T.
The average of short term fuel trim values plus long term fuel trim is less than -27% during 450 seconds out of 750 second test period for A/T.

Action Taken When the DTC Sets

The Malfunction Indicator Lamp (MIL) will illuminate.
The ECM will record operating conditions at the time the diagnostic fail. This information will be stored in the Freeze Frame and Failure Records buffers.
A history DTC is stored.

Conditions for Clearing the MIL/DTC

The MIL will turn off at the end of three consecutive validation cycles in which the diagnostic runs without a fault.
A history DTC will clear after 40 warm up cycles without a fault.
DTC(s) can be cleared by using the scan tool.

Diagnostic Aids

Important : After repairs, use the scan tool Fuel Trim Reset function to reset the long-term fuel trim to 128 (0%).

Check for poor connection at the ECM. Inspect the harness connectors for the following conditions:

Backed-out terminals.
Improper mating.
Broken locks.
Improperly formed.
Damaged terminals.
Poor terminal-to-wire connection.

Inspect the wiring harness for damage. If the harness appears to be OK, observe the O2S display on the scan tool while moving the connectors and the wiring harness related to the engine harness. A change in the display will indicate the location of the fault.

DTC P0172 - Fuel Trim System Too Rich

Step	Action	Value(s)	Yes	No
1	Perform the Diagnostic System Check. Is the system check complete?	-	Go to Step 2	Go to "Diagnostic System Check"
2	Install the scan tool to the Data Link Connector (DLC). Turn the ignition ON. Are any component related Diagnostic Trouble Codes (DTCs) set?	-	Go to applicable DTC table	Go to Step 3
3	With the engine running, operate the vehicle until the LOOP STATUS indicates closed. Is the Long Term Fuel Trim value above the specified value?	-30%	Go to Step 4	Go to Step 5
4	Turn the ignition switch ON, with the engine OFF. Review the Freeze Frame data and note the parameters. Operate the vehicle within the Freeze Frame conditions and Conditions for Setting The DTC as noted. Does the Long Term Fuel Trim value above the specified value while operating under the specified conditions?	-30%	Go to Step 19	Go to Step 5
5	Visually/physically check the air cleaner filter for excessive dirt or being plugged and repair as needed. Is the repair complete?	-	Go to Step 19	Go to Step 6
6	Visually/physically check the air intake system for collapsed or restricted and repair as needed. Is the repair complete?	-	Go to Step 19	Go to Step 7
7	Inspect the throttle body inlet for damaged or foreign objects which may partially block the airflow and repair as needed. Is the repair complete?	-	Go to Step 19	Go to Step 8
8	Turn the ignition OFF. Inspect the throttle bore, throttle plate and Idle Air Control (IAC) passages for clocking and foreign objects and repair as needed. Is the repair complete?	-	Go to Step 19	Go to Step 9
9	Start the engine with the vehicle in park or neutral and A/C off and note the idle quality. Is a low or unsteady idle being experienced?	-	Go to Step 10	Go to Step 12
10	Check the IAC valve or MTIA performance. Was the repair necessary and completed?	-	Go to Step 19	Go to Step 11
11	Turn the ignition OFF. Disconnect the Manifold Absolute Pressure (MAP) sensor electrical connector. Start the engine. Operate the vehicle in Closed Loop while monitoring the Long Term Fuel Trim value. Does the Long Term Fuel Trim value increase above the specified value?	-30%	Go to Step 18	Go to Step 12
12	Turn the ignition ON. Slowly press the acceleration pedal. Does the Throttle Position (TP) sensor display increase steady and evenly from its minimum voltage at closed throttle to its maximum voltage at Wide-Open Throttle (WOT).	-	Go to Step 13	Go to Step 17
13	Perform the Fuel System Diagnosis. If the table isolate a problem, repair as needed. Is the repair complete?	-	Go to Step 19	Go to Step 14
14	Perform the Evaporative Emission (EVAP) Control System Diagnosis. If the table isolate a problem, repair as needed. Is the repair complete?	-	Go to Step 19	Go to Step 15
15	Perform the Fuel Injector Balance Test. If the table isolate a problem, repair as needed. Is the repair complete?	-	Go to Step 19	Go to Step 16
16	Remove the oxygen sensor. Visually/physically inspect the HO2S for silicone contamination. Notice : This will be indicated by a powdery white deposit on the portion of the HO2S exposed to the exhaust stream. If contamination is present on the HO2S, find the source and repair as needed. Is the repair complete?	-	Go to Step 19	Go to "Diagnostic Aids"
17	Check the TP sensor mounting screws. If they are too loose or missing tighten or replace them as needed. If the screws are OK, replace the TP sensor. Is the repair complete?	-	Go to Step 19	-
18	Turn the ignition OFF. Replace the MAP sensor. Is the repair complete?	-	Go to Step 19	-
19	Using the scan tool, clear the Diagnostic Trouble Codes (DTCs). Start the engine and idle at normal operating temperature. Operate the vehicle within the Conditions for setting this DTC as specified in the supporting text. Does the scan tool indicate that this diagnostic has run and passed?	-	Go to Step 20	Go to Step 2
20	Check if any additional DTCs are set. Are any DTCs displayed that have not been diagnosed?	-	Go to applicable DTC table	System OK

Diagnostic Trouble Code (DTC) P0222

Main Throttle Idle Actuator (MTIA) Low Voltage

Circuit Description

The Main Throttle Idle Actuator (MTIA) assembly contains an idle speed control (ISC) motor that is used to control the engine speed at idle. The engine control module (ECM) commands the ISC motor to adjust the throttle angle for idle speed control. The throttle position (TP) sensor and the ISC motor position sensor are also integrated into the MTIA. Both of the position sensors share a common 5-volt reference circuit and a common low reference circuit. Each position sensor has an individual signal circuit, which provides the ECM with a signal voltage proportional to throttle plate movement. If the ECM detects the ISC motor position sensor signal voltage is too low, this DTC sets.

Conditions for Running the DTC

Ignition switch is ON.

Conditions for Setting the DTC

The ECM detects that the ISC motor position signal voltage is less than 0.257 V.

Action Taken When the DTC Sets

The Malfunction Indicator Lamp (MIL) will illuminate.
The ECM will record operating conditions at the time the diagnostic fails. The information will be stored in the freeze frame and failure records buffers.
A history DTC is stored.

Conditions for Clearing the MIL/DTC

The MIL will turn off at the end of 3 consecutive validation cycles in which the diagnostic runs without a fault.
A history DTC will clear after 40 warm up cycles without a fault.
DTC(s) can be cleared by using the scan tool.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

Do NOT use the low reference circuit in the component harness connector for this test. Damage to the control module may occur due to excessive current draw.
The 5-volt reference circuits are internally connected within the controller. Other sensors that share the 5-volt reference circuit may also have DTCs set. Disconnecting a sensor on the shared 5-volt reference circuit may isolate a shorted sensor. Review the electrical schematic and diagnose the shared circuits and sensors.

DTC P0222 - Main Throttle Idle Actuator (MTIA) Low Voltage

Step	Action	Value(s)	Yes	No
1	Did you perform the Diagnostic System Check?	-	Go to Step 2	Go to "Diagnostic System Check"
2	Turn ON the ignition, with the engine OFF. Observe the ISC motor position sensor parameter with a scan tool. Is the voltage less than the specified value?	0.3V	Go to Step 4	Go to Step 3
3	Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition?	-	Go to Step 4	Go to "Intermittents"
4	Turn OFF the ignition. Disconnect the throttle body harness connector. Turn ON the ignition, with the engine OFF. Connect a test lamp between the 5-volt reference circuit of the ISC motor position sensor and a good ground. Connect a DMM to the probe of the test lamp and a good ground. Is the voltage more than the specified value?	4.8 V	Go to Step 5	Go to Step 6
5	Turn OFF the ignition. Connect a 3-amp fused jumper wire between the signal circuit and the 5 volt reference circuit of the ISC motor position sensor. Turn ON the ignition, with the engine OFF. Observe the ISC motor position sensor parameter with a scan tool. Is the voltage within the specified range?	4.8~5.2 V	Go to Step 8	Go to Step 7
6	Test the 5-volt reference circuit of the ISC motor position sensor and all shared 5-volt reference circuits for the following: An open A short to ground High resistance Did you find and correct the condition?	-	Go to Step 12	Go to Step 9
7	Test the signal circuit of the ISC motor position sensor for the following: A short to ground An open High resistance Did you find and correct the condition?	-	Go to Step 12	Go to Step 9
8	Test for shorted terminals and for poor connections at the throttle body. Did you find and correct the condition?	-	Go to Step 12	Go to Step 10
9	Test for shorted terminals and for poor connections at the engine control module (ECM). Did you find and correct the condition?	-	Go to Step 12	Go to Step 11
10	Replace the MTIA assembly. Did you complete the replacement?	-	Go to Step 12	-
11	Replace the ECM. Did you complete the replacement?	-	Go to Step 12	-
12	Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition?	-	Go to Step 2	Go to Step 13
13	Check if any additional DTCs are set. Are there any DTCs that have not been diagnosed?	-	Go to applicable DTC table	System OK

Diagnostic Trouble Code (DTC) P0223

Main Throttle Idle Actuator (MTIA) High Voltage

Circuit Description

Conditions for Running the DTC

Ignition switch is ON.

Conditions for Setting the DTC

The ECM detects that the ISC motor position signal voltage is higher than 4.9 V.

Action Taken When the DTC Sets

The Malfunction Indicator Lamp (MIL) will illuminate.
The ECM will record operating conditions at the time the diagnostic fails. The information will be stored in the freeze frame and failure records buffers.
A history DTC is stored.

Conditions for Clearing the MIL/DTC

The MIL will turn off at the end of 3 consecutive validation cycles in which the diagnostic runs without a fault.
A history DTC will clear after 40 warm up cycles without a fault.
DTC(s) can be cleared by using the scan tool.

Test Description

The number below refers to the step number on the diagnostic table.

The 5-volt reference circuits are internally connected within the controller. Other sensors that share the 5-volt reference circuit may also have DTCs set. Disconnecting a sensor on the shared 5-volt reference circuit may isolate a shorted sensor. Review the electrical schematic and diagnose the shared circuits and sensors.

DTC P0223 - Main Throttle Idle Actuator (MTIA) High Voltage

Step	Action	Value(s)	Yes	No
1	Did you perform the Diagnostic System Check?	-	Go to Step 2	Go to "Diagnostic System Check"
2	Turn the ignition ON, with the engine OFF. Observe the ISC motor position sensor parameter with a scan tool. Is the voltage more than the specified value?	4.8 V	Go to Step 4	Go to Step 3
3	Observe the Freeze Frame/Failure Records for this DTC. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition?	-	Go to Step 4	Go to "Intermittents"
4	Turn OFF the ignition. Disconnect the throttle body harness connector. Turn ON the ignition, with the engine OFF. Measure the 5 V reference circuit of the ISC motor position sensor to a good ground with a DMM. Is the voltage more than the specified value?	5.2 V	Go to Step 7	Go to Step 5
5	Measure the signal circuit of the ISC motor position sensor to a good ground with a DMM. Is the voltage more than the specified value?	0.5 V	Go to Step 8	Go to Step 6
6	Turn OFF the ignition. Measure the low reference circuit of the ISC motor position sensor to a good ground with a DMM. Is the resistance less than the specified value?	3 ohms	Go to Step 10	Go to Step 9
7	Test the 5 V reference circuit of the ISC motor position sensor for short to voltage. Did you find and correct the condition?	-	Go to Step 14	Go to Step 11
8	Test the signal circuit of the ISC motor position sensor for a short to voltage. Did you find and correct the condition?	-	Go to Step 14	Go to Step 11
9	Test the low reference circuit of the ISC motor position sensor for an open and for a high resistance. Did you find and correct the condition?	-	Go to Step 14	Go to Step 11
10	Test for shorted terminals and for poor connections at the throttle body. Did you find and correct the condition?	-	Go to Step 14	Go to Step 12
11	Test for shorted terminals and for poor connections at the engine control module (ECM). Did you find and correct the condition?	-	Go to Step 14	Go to Step 13
12	Replace the MTIA assembly. Did you complete the replacement?	-	Go to Step 14	-
13	Replace the ECM. Did you complete the replacement?	-	Go to Step 14	-
14	Clear the DTCs with a scan tool. Turn OFF the ignition for 30 seconds. Start the engine. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records. Did the DTC fail this ignition?	-	Go to Step 2	Go to Step 15
15	Check if any additional DTCs are set. Are there any DTCs that have not been diagnosed?	-	Go to applicable DTC table	System OK

Diagnostic Trouble Code (DTC)

P0261 Injector 1 Low Voltage

P0264 Injector 2 Low Voltage

P0267 Injector 3 Low Voltage

P0270 Injector 4 Low Voltage

Circuit Description

The engine control module (ECM) has injector driver circuits for each cylinder, each of which controls an injector. When a driver circuit is grounded by the ECM, the injector is activated. The ECM monitors the current in each driver circuit. The ECM measures a voltage drop through a fixed resistor and controls it. The voltage on each driver is monitored to detect a fault. If the voltage is not what the ECM expects to monitor on the circuit, a Diagnostic Trouble Code (DTC) is set.

Conditions for Running the DTC

Engine is running.

Conditions for Setting the DTC

An open or a short to ground condition exists in the injector circuit.

Action Taken When the DTC Sets

The Malfunction Indicator Lamp (MIL) will illuminate.
The ECM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Records buffers.
A history DTC is stored.

Conditions for Clearing the MIL/DTC

The MIL will turn off at the end of a consecutive validation cycle in which the diagnostic runs without a fault.
A history DTC will clear after 40 warm up cycles without a fault.
DTC(s) can be cleared by using the scan tool.

Diagnostic Aids

An injector driver circuit that is open or shorted to ground will causes a DTC to set. It will also cause a misfire due to an inoperative injector. A misfire DTC should also be set indicating which injector is inoperative.

Long-term and short-terms fuel trims that are excessively high or low are a good indication that an injector is malfunctioning. Refer to "Fuel Injector Balance Test" in this section to check for malfunctioning injectors.

The injector resistance tested at the ECM connection is slightly more than it tested directly at the injector because it includes resistance of the harness wires. The normal value is about 13.5Ω.

DTC P0261 - Injector 1 Low Voltage

DTC P0264 - Injector 2 Low Voltage

DTC P0267 - Injector 3 Low Voltage

DTC P0270 - Injector 4 Low Voltage

Step	Action	Value(s)	Yes	No
1	Perform the Diagnostic System Check. Is the system check complete?	-	Go to Step 2	Go to "Diagnostic System Check"
2	Attempt to start the engine. Does the engine start?	-	Go to Step 3	Go to "Engine Cranks But Will Not Run"
3	Install a scan tool and clear the Diagnostic Trouble Codes (DTCs). Idle the engine for one minute. Does the DTC reset?	-	Go to Step 5	Go to Step 4
4	Review the Freeze Frame data with the ignition ON and the engine OFF and note the parameters. Operate the vehicle within the Freeze Frame conditions as notes. Does the DTC reset?	-	Go to Step 5	Go to "Diagnostic Aids"
5	Turn the ignition switch to LOCK. Check for an open or a short to ground in the wire between the injector connector terminal 2 and the corresponding ECM connector terminal. Is the problem found?	-	Go to Step 7	Go to Step 6
6	Turn the ignition switch to LOCK. Check for an open or a short to ground in the wire between the injector connector terminal 1 and the battery positive. Is the problem found?	-	Go to Step 7	Go to Step 8
7	Repair the wire or the connector terminal as needed. Clear any DTCs from ECM. Perform the Diagnostic System Check. Is the repair complete?	-	Go to Step 10	-
8	Replace the injector. Clear any DTCs from ECM. Perform the Diagnostic System Check. Does the DTC reset?	-	Go to Step 9	Go to Step 10
9	Turn the ignition switch to LOCK. Replace the ECM. Perform the Diagnostic System Check. Is the repair complete?	-	Go to Step 10	-
10	Check if any additional DTCs are set. Are any DTCs displaced that have not been diagnosed?	-	Go to applicable DTC table	System OK

Diagnostic Trouble Code (DTC)

P0262 Injector 1 High Voltage

P0265 Injector 2 High Voltage

P0268 Injector 3 High Voltage

P0271 Injector 4 High Voltage

Circuit Description

Conditions for Running the DTC

Engine is running.

Conditions for Setting the DTC

A short to battery condition exists in the injector circuit.

Action Taken When the DTC Sets

The Malfunction Indicator Lamp (MIL) will illuminate.
The ECM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Records buffers.
A history DTC is stored.

Conditions for Clearing the MIL/DTC

The MIL will turn off at the end of a consecutive validation cycle in which the diagnostic runs without a fault.
A history DTC will clear after 40 warm up cycles without a fault.
DTC(s) can be cleared by using the scan tool.

Diagnostic Aids

An injector driver circuit that is shorted to voltage will causes a DTC to set. It will also cause a misfire due to an inoperative injector. A misfire DTC should also be set indicating which injector is inoperative.

The injector resistance tested at the ECM connection is slightly more than it tested directly at the injector because it includes resistance of the harness wires. The normal value is about 13.5Ω.

DTC P0262 - Injector 1 High Voltage

DTC P0262 - Injector 2 High Voltage

DTC P0268 - Injector 3 High Voltage

DTC P0271 - Injector 4 High Voltage

Step	Action	Value(s)	Yes	No
1	Perform the Diagnostic System Check. Is the system check complete?	-	Go to Step 2	Go to "Diagnostic System Check"
2	Attempt to start the engine. Does the engine start?	-	Go to Step 3	Go to "Engine Cranks But Will Not Run"
3	Install a scan tool and clear the Diagnostic Trouble Codes (DTCs). Idle the engine for one minuet. Does the DTC reset?	-	Go to Step 5	Go to Step 4
4	Review the Freeze Frame data with the ignition ON and the engine OFF and note the parameters. Operate the vehicle within the Freeze Frame conditions as notes. Does the DTC reset?	-	Go to Step 5	Go to "Diagnostic Aids"
5	Turn the ignition switch to LOCK. Check for a short to voltage in the wire between the injector connector terminal 1 and the corresponding ECM connector terminal. Is the problem found?	-	Go to Step 6	Go to Step 7
6	Repair the wire or the connector terminal as needed. Clear any DTCs from ECM. Perform the Diagnostic System Check. Is the repair complete?	-	Go to Step 9	-
7	Replace the injector. Clear any DTCs from ECM. Perform the Diagnostic System Check. Does the DTC reset?	-	Go to Step 8	Go to Step 9
8	Turn the ignition switch to LOCK. Replace the ECM. Perform the Diagnostic System Check. Is the repair complete?	-	Go to Step 9	-
9	Check if any additional DTCs are set. Are any DTCs displaced that have not been diagnosed?	-	Go to applicable DTC table	System OK