Checking components
ECM-959F is pretty much always stored as a result of another fault on the CAN network or as a subsequent diagnostic trouble code for an already detected fault on one of the signals from the accelerator pedal position sensor. Check whether any diagnostic trouble codes have been stored that indicate a fault on the CAN network, ECM-901A, ECM-902A, ECM-911A, ECM-912A, ECM-E003 and/or ECM-E000. If so, these diagnostic trouble codes must be fault traced first. If any diagnostic trouble code has been stored that indicates a fault in the accelerator pedal position sensor, ECM-9180, ECM-9520, ECM-9530, ECM-9540 and/or ECM-958F, these are to be fault traced first. Otherwise, continue as follows.
Using the diagnostic trouble code counter and parameters in VIDA vehicle communication, check whether the fault is intermittent or permanent. Compare the parameters "Accelerator pedal, PWM (via ETM)" and "Accelerator pedal, Analogue". These should under no circumstances differ by more than 10% unless the analogue signal is undergoing change, e.g. during throttle application, when a large deviation between the two signals is permitted.
If the diagnostic trouble code (DTC) is permanent:
If diagnostic trouble code ECM-959F is stored as the only trouble code, it indicates that both the engine control module (ECM) and electronic throttle module (ETM) detect that the signals from the accelerator pedal position sensor are OK, even though the signal that the electronic throttle module (ETM) sends back to the engine control module (ECM) via the CAN network is faulty. This is a highly unlikely situation. Search for a fault that could cause the signal to be faulty yet still within the electrical fault limits.
- Check the cables and connections between the electronic throttle module (ETM) and the engine control module (ECM) for contact resistance and corrosion.
- Check whether there is any potential difference for ground connections and voltage supplies between the engine control module (ECM) and the electronic throttle module (ETM).
HINT: The signal cables between the accelerator pedal position sensor and the engine control module (ECM) do not need to be checked. ECM-958F is generated if there is a fault on these cables.
If the diagnostic trouble code (DTC) is intermittent:
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.
HINT: Using VIDA vehicle communication, check that the parameters "Accelerator pedal, PWM", "Accelerator pedal, PWM (via ETM)" and "Accelerator pedal, Analogue" indicate 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 upgraded software, released during year 2006 or later, is available, the solution may be to download the upgraded software. Since detection time has been increased from 0.5 to 0.9 seconds, the upgraded software will be much more tolerant to short, intermittent disruptions.
Remedy as necessary.
Other information
Caution: In order for Electronic throttle module (ETM) to reset any reconfigurations as well as delete internally stored problems, the following must be performed:
- Turn off the ignition and then wait three minutes for the main relay or system relay to release the voltage feed to, among others, Electronic throttle module (ETM).
- Then turn on the ignition and turn it off again.
- Wait another three minutes, but if the electric cooling fan is running you have to wait another two minutes after the cooling fan has stopped, to ensure that Electronic throttle module (ETM) is shut off correctly.
If this is not done correctly, diagnostic trouble codes may remain even after deletion of diagnostic trouble codes as well as any reconfiguration, despite the problem being fixed.
- Continue
Refer to Information