Checking engine control components
Check, using the diagnostic trouble code (DTC) statuses, if the fault is intermittent or permanent.
Permanent fault
Check the cable between engine control module (ECM) terminal #B25 and accelerator pedal position sensor terminal #2 for open circuit, short circuit to supply voltage or short circuit to ground depending on the type of fault detected. In conjunction with this, check the cable between engine control module (ECM) terminal #A56 and electronic throttle module (ETM) terminal #1 since #B25 and #A56 are internally connected in the engine control module (ECM) and a short circuit on #A56 will generate this diagnostic trouble code.
Intermittent fault
Use the diagnostic trouble codes' frozen values as well as the counters, to determine the driving conditions when the problem was detected the first time and how often the problem has occurred. The values show the problem's current status and how intermittent the problem is. The operating conditions can be, for example, whether the engine was running, what the speed of the vehicle was and what the battery voltage in the system was. This information can facilitate searching for an intermittent fault.
Check whether the engine control module (ECM) has stored any other diagnostic trouble codes that indicate a fault in the pulse width modulated (PWM) signal from the accelerator pedal position sensor. In most cases, diagnostic trouble code (DTC) ECM-918F is stored, together with ECM-9520, which indicates that even the Electronic throttle module (ETM) has detected a problem with the pulse width modulated (PWM) signal. If only diagnostic trouble codes (DTCs), ECM-9520 and ECM-918F are stored, this indicates that the fault has occurred for longer than 0.3 seconds, but for less than 1 second. If the fault occurred for more than 1 second, ECM-951F would also be stored with these trouble codes.
HINT: Check, using VIDA vehicle communication that the parameter "Accelerator pedal, PWM (%)" shows the correct values. To aid fault tracing, use Component specifications when measuring and checking relevant components and use Wiring diagram, Signal description and Breakout box to measure and control signals to and front the control module or its components.
For markets where the upgraded software, released during 2006 or later, is available, the solution may be to load the upgraded software. As the detection time has increased from 0.3 to 0.7 seconds, the upgraded software becomes more tolerant towards short intermittent interference among other things.
Remedy as necessary.
Other information:
- To access / replace the accelerator pedal (AP) position sensor, see Replacing the accelerator pedal module .
- For information about signals, see Signal specification .
- See Identifying upgraded software ECM/ETM
- See Checking wiring and terminals
Caution: In order for Electronic throttle module (ETM) to reset any reconfigurations as well as delete internally stored problems, the following must be performed:
- Ignition off, wait three minutes so that the main relay / system relay releases the voltage feed to, among other, Electronic throttle module (ETM).
- Then turn on the ignition and turn it off again.
- Wait another three minutes. If the electric cooling fan is running, you have to wait another two minutes after the electric cooling fan has stopped, to make sure that Electronic throttle module (ETM) has been shut off correctly.
If this is not done correctly, diagnostic trouble codes may remain even after deleting diagnostic trouble codes and any reconfiguration may remain, despite the problem being fixed.
- Continue
Refer to Information