Diagnostic trouble code (DTC) information ECM-912A

Condition

Fig 1: Identifying Signal Missing Between ETM And ECM

Courtesy of VOLVO CARS OF NORTH AMERICA.

The control modules communicate with each other in a network via standardized serial communication - CAN (controller area network). If the electronic throttle module (ETM) has not received a CAN signal from the engine control module (ECM) within 0.5 seconds of the ignition being switched on or any of the engine control module (ECM) signals are missing for more than 0.3 seconds, it sends this information to the engine control module (ECM), which then stores diagnostic trouble code ECM-912A, no signal.

For upgraded software, released during year 2006 or later, the above detection times are changed. Control at ignition on is increased from 0.5 to 4 seconds as well as control of if any signal is lost during operation is increased from 0.3 to 0.9 seconds.

See Identifying upgraded software ECM/ETM

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

See Function

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.

The following only applies in combination with diagnostic trouble code ECM 9180 and/or ECM-918F:

Throttle closed.
The electronic throttle module (ETC) deactivates the throttle motor control, which means that the throttle is not actuated and assumes its mechanical stop position. This means about 20% throttle opening. This reconfiguration is always followed by fuel cut-off.

For upgraded software, released during year 2006 or later, the reconfiguration, Closing of throttle at braking, has been removed.

See Identifying upgraded software ECM/ETM

Possible Source

the power supply to the engine control module (ECM)
loose connections or contact resistance in the terminals for the CAN
open-circuit in one or both CAN signal cables
short-circuit to ground, voltage or each other in one or both of the CAN signal cables
interference on the signal 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.

See Information about combined diagnostic trouble codes (DTCs)

Fault symptom[s]

the accelerator pedal (AP) is ignored when braking
the cruise control cannot be activated
uneven idle
jerks during engine braking
the ETS warning lamp lights (V70 -2000 only).

The following only applies in combination with diagnostic trouble codes (DTCs) ECM-9180 or ECM-918F:

very poor accelerator response
maximum speed approximately 50 km/h.