Faulty Signal
Faulty signal
Frozen values and counter for diagnostic trouble codes.
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. Driving conditions may be, e.g., if the engine was running, what speed the vehicle had, or how long the driving distance was.
Counter
The counters are used to determine the problem's status. For general information about the counters, see: Counters, description Counters, Description
Counter 1 indicates the number of drive cycles without fault since the fault was last validated.
If counter 1 is the same as 0, this means that the fault has been detected in this operating cycle (permanent fault). If no troubleshooting or repair has been performed in the vehicle in this driving cycle, the problem is probably in the vehicle.
If counter 1 is over 0, this indicates that the problem has not been detected in this driving cycle (intermittent problem). The problem has existed earlier but is not active right now.
Then check counter 4. Counter 4 indicates number of driving cycles with problem since the problem was validated for the first time.
If the number of driving cycles with problems is high, this indicates an intermittent recurring problem, which means greater possibility of regenerating the problem in the workshop.
If the number of driving cycles with problems is low, this indicates an intermittent temporary problem, which means small possibility of regenerating the problem.
Hint: Counter 3 indicates number of driving cycles since first time that the problem occurred. If the value for counter 3 is divided by the value for counter 4 , the intensity of the problem is obtained. The higher the value, the higher the problem intensity. A high problem intensity indicates that the malfunction recurs often.
Counter 5 can be used for more exact determination of when the problem occurred. To compare counter 5 for diagnostic trouble codes indicates in which order the diagnostic trouble codes were stored.
5-cyl. non-turbo engines
For model year 1999, only counter 1 and 2 are available.
Frozen values
The frozen values show the driving conditions when the control module detected the problem the first time. Check using the frozen values that the diagnostic trouble code has not been caused accidentally during troubleshooting of the vehicle. If the driving distance is 0 km/miles, this indicates that the problem has occurred at the control modules' start-up of the CAN-net, when reception of a relevant value has not been possible. This also applies to other values that come via the CAN-network. In these cases, counter 5 can be used to determine when the problem was generated.
If the diagnostic trouble code has been caused during this troubleshooting, it may be due to, e.g., disconnected component, too low or high battery voltage, or that some control module has been disconnected.
If the diagnostic trouble code has been stored since before, there has likely been a problem or interference, which has resulted in the control module detecting a problem.
For general information about frozen value, see: Information Information
For information about frozen values.
- Turbo engines and 6-cyl. non-turbo engines: Description of frozen values Me7 Description of Frozen Values ME7
- 5-cyl. non-turbo engines: Frozen values DENSO, description Description of Frozen Values DENSO
Read off the diagnostic trouble code's counter and frozen values by clicking on the symbol for VCT2000. Choose diagnostic trouble code in question.
Continue - DONE
------------------------
DONE - Checking the status
-------------------------------------------------
Checking the status
Hint: If diagnostic trouble code (DTC) ECM-9520 or ECM-9530 is stored in the engine control module (ECM), these diagnostic trouble codes (DTCs) must be fault-traced first.
- Ignition on.
Check whether the fault is permanent or intermittent. Read off the analog signal and the pulse width modulation (PWM) signal from the accelerator pedal (AP) position sensor.
Check that the difference between the signals is not more than approximately 4%. Check that the value is between 6-9% with unaffected accelerator pedal (AP) and between 85-90% with the accelerator pedal (AP) fully depressed.
Check the signals throughout the measurement range of the accelerator pedal (AP) position sensor (from completely released to completely depressed). Make the check using slow movements of the accelerator pedal (AP).
The fault is intermittent if the signals are correct.
Hint: A defective accelerator pedal (AP) position sensor is indicated if any of the returned signals deviates at a specific accelerator pedal (AP) angle.
Other information
Continue - Checking components
-------------------------------------------------
Checking components
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 or the analogue signal from the accelerator pedal position sensor.
If ECM-9180, ECM-9520, ECM-9530 and/or ECM-9540 are stored, these diagnostic trouble codes are to be fault traced first. Otherwise, continue as follows.
Using the diagnostic trouble code counter, check whether the fault is intermittent or permanent. Compare the parameters "Accelerator pedal, Analogue" and "Accelerator pedal, PWM". These should under no circumstances differ by more than 5% 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:
Search for a fault that could cause any of the signals to be faulty yet still within the electrical fault limits. Check the cables and connections between the accelerator pedal position sensor 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 accelerator pedal position sensor.
Check the cables and connections between the grounding point for the system relay and the accelerator pedal position sensor.
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. If the trouble code was stored when battery voltage was less than 10.5 V and engine speed was 0 rpm, it indicates that the fault may have occurred when the engine was started. This, in turn, indicates that the battery's charging status is not OK.
- Check the battery status.
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.
When ECM-958F is stored, the frozen values often indicate that the fault occurred when battery voltage was less than 12 V and engine speed was close to 0 rpm. If these operating conditions are found in the vehicle and upgraded software is available (released 2006 or later), the solution is to download the upgraded software. The upgraded software requires engine speed to be greater than 600 rpm for the test to be active.
Upgraded software could also be the solution if the trouble code was stored when the engine was running since detection time has been increased from 0.4 to 0.7 seconds. The upgraded software will also be much more tolerant to short, intermittent disruptions. If upgraded software is not available and the frozen values indicate that the fault occurred when battery voltage was low and engine speed was close to 0 rpm, fault tracing should focus on checking the vehicle's power supply, especially battery charge status.
Remedy as necessary.
Other information:
- To access or replace the system relay, see the location of components
- To access or replace the accelerator pedal (AP) position sensor: Replacing the accelerator pedal module Service and Repair
- Checking wiring and terminals Checking Wiring and Terminals
- Checking wiring and terminals 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:
- 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.
-------------------------------------------------