The Engine Control Module (ECM) determines linear wheel speed excessive variation. The wheel speed variation test detects at least one missing edge from the wheel speed sensor signal.

Check for the following conditions:

An open signal circuit of open PWM serial data line between the ECM and the EBCM will be the cause of this DTC.

The number(s) below refer to specific step(s) on the diagnostic table.

The Engine Control Module (ECM) determines linear wheel speed fail threshold. The ECM detects a good or failed wheel speed sensor under power conditions.

Check for the following conditions:

An open signal circuit of open PWM serial data line between the ECM and the EBCM will be the cause of this DTC.

The number(s) below refer to specific step(s) on the diagnostic table.

The Engine Control Module (ECM) is the control center of the fuel injection system. It constantly looks at the information from various sensors, and controls the systems that affect vehicle performance. The ECM also performs the diagnostic function of the system. It can recognize operational problems, alert the driver through the Malfunction Indicator Lamp (MIL) (Check Engine), and store a Diagnostic Trouble Code (DTC) or DTCs which identify the problem areas to aid the technician in making repairs. The ECM received incorrect message identification.

The Engine Control Module (ECM) supplies a voltage of about 0.45 volts between terminals M12 and M29 (if measured with a 10 megohm digital voltmeter, this may read as low as 0.32 volts). The Front Heated Oxygen Sensor (HO2S1) varies the voltage within a range of about 1 volt if the exhaust is rich, down through about 0.10 volts if the exhaust is lean.

In internal circuitry of the Engine control Module (ECM) can identify if the vehicle fuel system is capable of cutoff amount of the fuel supply during deceleration. When a Decel Fuel Cutoff (DFCO) mode of operation is requested during Closed Loop operation, the ECM will cutoff the fuel supply to the engine. Under these conditions the ECM should detect a lean condition. If the ECM detect a rich condition at this time, Diagnostic Trouble Code (DTC) P2297 will set. Damaged fuel pressure regulator and faulty injector will be the cause of this DTC.

The DTC P2297 or rich exhaust is most likely caused by one of the following items:

The Engine Control Module (ECM) is the control center of the fuel injection system. It constantly looks at the information from various sensors, and controls the systems that affect vehicle performance. The ECM also performs the diagnostic function of the system. It can recognize operational problems, alert the driver through the Malfunction Indicator Lamp (MIL) (Check Engine), and store a Diagnostic Trouble Code (DTC) or DTCs which identify the problem areas to aid the technician in making repairs. An Electrically Erasable Programmable Read Only Memory (EEPROM) is used to house the program information and the calibrations required for engine, transmission, and powertrain diagnostics operation. The ECM monitors EEPROM reset flag and Lower Power Counter I/C overflow bits. If the ECM detects if Lower Power Counter I/C has been reset due to battery disconnect or Lower Power Counter I/C malfunction, the Diagnostic Trouble Code (DTC) will stored.

Counter Reset

Counter Error

The Serial Peripheral Interface (SPI) communication is used internally by the Engine Control Module (ECM) to send message between the engine processor and the automatic transaxle processor. Included in each message sent between the two processor is a checksum of the message. Both the engine processor automatic transaxle processor will compare this checksum value with calculated checksum. If the checksum do not match, the processor will review the new data as being corrupted and ignore the value. The processor then use the previous message. The receiving processor will then send a message to the sending processor informing it that its last message was corrupted.

The ECM monitor periodic TCM status message and if message is not received fail counter incremented and Diagnostic trouble Code (DTC) will stored.

The Engine Control Module (ECM) is the control center of the fuel injection system. It constantly looks at the information from various sensors, and controls the systems that affect vehicle performance. The ECM also performs the diagnostic function of the system. It can recognize operational problems, alert the driver through the Malfunction Indicator Lamp (MIL) (Check Engine), and store a Diagnostic Trouble Code (DTC) or DTCs which identify the problem areas to aid the technician in making repairs. The ECM detects communication link failure with immobilizer control unit.