With Generic Scan Tool
Throttle Valve Control Module J338, Checking
NOTE: Use only gold-plated terminals when servicing terminals in harness connector of throttle valve control module.
Recommended special tools and equipment
- multimeter
- Wiring diagram
Test Requirements
- The respective fuses of Motronic Engine Control Module (ECM) -J220- must be OK:
- Battery voltage must be at least 12.5 Volts.
- All electrical consumers such as, lights and rear window defroster must be switched off.
- A/C switched off.
- Ground (GND) connections between engine and chassis must be OK.
- Throttle valve must not be damaged or dirty.
- Coolant temperature must be at least 80°C
Test Procedure
- Perform a preliminary check to verify the customer's complaint.
Start diagnosis
Function
Throttle valve operation occurs by an electric motor (Throttle Position (TP) Actuator V60) in the Throttle Valve Control Module J338. It is operated by the Motronic Engine Control Module (ECM) J220 and the Throttle Position (TP) Sensor G69/Throttle Position (TP) Sensor G88.
The Throttle Valve Control Module J338 is made up of the following components:
- Throttle Position (TP) Actuator V60
- Throttle Position (TP) Sensor G69
- Throttle Position (TP) Sensor G88
- The Throttle Valve Control Module J338 cannot be serviced separately and must be serviced as a unit.
Function test
- Connect the scan tool.
- Switch ignition on.
- Using the scan tool, check the throttle valve position (absolute) at idle stop:
- Slowly depress accelerator pedal up to Wide Open Throttle (WOT) stop while observing the percentage display. The percentage display must increase uniformly.
- Using the scan tool, check specified value of throttle valve position (absolute) at Wide Open Throttle (WOT) stop:
- End diagnosis and switch ignition off.
If specified values are not obtained:
- Remove the Throttle Valve Control Module J338 far enough so that the electrical connector terminals are reached.
- Disconnect Throttle Valve Control Module J338 electrical connector -arrow-.
Checking resistance
- Using multimeter, check Throttle Position (TP) actuator -V60- at the Throttle Valve Control Module J338 terminals 1 to 2 for resistance.
Specified value: 1.0 to 5.0 Ohms (at 20°C)
If specified value is not obtained:
- Replace Throttle Valve Control Module -J338-.
If specified value is obtained:
- Check voltage supply of throttle valve control module and wiring to control module.
If voltage supply and wires are OK:
- Replace Motronic Engine Control Module (ECM) -J220-.
Checking voltage supply and wiring
- Switch ignition on
- Using multimeter, check Throttle Position (TP) actuator -V60- at the Throttle Valve Control Module J338 terminals 4 to 8 for voltage.
Specified value: at least 4.5V
- Switch ignition off
If the specification was not obtained:
Checking wiring
If the manufacturers test box is being used. Perform the following step.
- Install the Adapter F/VAG1598 (68 Pin) VAG1598/22.
If the manufacturers test box is not being used. Perform the following step.
- Remove the Motronic Engine Control Module (ECM) J220.
- Using a Multimeter, check the Throttle Position (TP) Actuator V60 at Throttle Valve Control Module J338 electrical harness connector terminals to the Motronic Engine Control Module (ECM) J220 electrical harness connector T80 terminals for an open circuit according to the wiring diagram.
Specified value: 1.5 ohms max
If the specification was not obtained:
- Check the wiring for a short circuit to each other, Battery (+), or Ground (GND).
- If necessary, repair the faulty wiring connection.
- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
If no malfunction is detected in the wiring and if the voltage supply was not OK:
- Replace the Throttle Valve Control Module J338.
- Erase the DTC memory.
- Perform a road test to verify repair.
If the DTC does not return:
- Repair complete, Generate readiness code.
- End diagnosis
If the DTC does return and no malfunction is detected in the wiring and the voltage supply was OK:
- Replace the Motronic Engine Control Module (ECM) J220.
- Assembly is performed in the reverse of the removal.
Final procedures
After the repair work, the following work steps must be performed in the following sequence:
1. Check the DTC memory.
2. If necessary, erase the DTC memory.
3. If the DTC memory was erased, generate readiness code.
- End of diagnosis.