Diagnostic Trouble Code (DTC) Information

Diagnostic trouble code (DTC) information ECM-902A

Condition




The control modules communicate with each other in a network via standardized serial communication - CAN (controller area network). If the engine control module (ECM) detects that any of the electronic throttle module (ETM) signals disappear during operation for more than 0.5 seconds and engine speed is greater than 600 rpm, it stores diagnostic trouble code ECM-902A, no signal.
If the engine control module (ECM) has not received a CAN signal from the electronic throttle module (ETM) within 1 second of the engine being started and engine speed exceeding 600 rpm, diagnostic trouble code ECM-902A (high signal) is generated.
If the engine control module (ECM) has not received a system relay deactivation request from the electronic throttle module (ETM) within 10 seconds of the ignition being switched off, diagnostic trouble code ECM-902A low signal is generated.
For upgraded software, released during year 2006 or later, some of the above detection times are changed. Control during operation is increased from 0.5 to 0.9 seconds as well as control at start is increased from 1 to 1.5 seconds.

For more information about the electronic throttle system and related components such as the electronic throttle module, accelerator pedal position sensor, brake light switch, clutch pedal position sensor, and brake pedal position sensor: Design Design

Substitute value

Fuel cut-off that follows accelerator pedal position.
Engine speed is regulated via fuel cut-off by deactivating the injectors one at a time. Engine speed is determined by gas pedal position sensor position and engine speed is maximized to about 5000 rpm.
This reconfiguration can cause the engine to idle very unevenly since the engine control module (ECM) regulates engine speed by cutting of the fuel to the cylinders individually. Do not confuse this reconfiguration (engine behavior) with an actual driveability problem that was present before reconfiguration.

Closing of throttle during braking.
The accelerator pedal position is ignored when the brake pedal is depressed.

Throttle follows accelerator pedal position.
The throttle and accelerator pedal are used as if they were mechanically connected. This reconfiguration is always followed by fuel cut-off.

Cruise control off.
Cruise control off during entire operating cycle in which fault was detected. If the fault is no longer present, the function is available the next time the car is started.
For upgraded software, released in 2006 or later, adjustments have been made to substitute values. In driving cycles when the fault is active, fuel shut-off that follows the accelerator pedal position will be activated.

Possible source
- the power supply to the throttle unit
- loose connections or contact resistance in the terminals for the CAN
- interference on the CAN signal wiring
- Damaged CAN cables.
- defective node in the Control area network (CAN)
- This diagnostic trouble code is generated in combination with other trouble codes. Information on the possible root cause is described.

Fault symptom[s]
- the accelerator pedal (AP) is ignored when braking
- the cruise control cannot be activated
- uneven idle
- jerks during engine braking
- ETS warning lamp lit.