Throttle Valve Control Module, Checking
Note. Use only gold-plated terminals when servicing terminals in harness connector of throttle valve control module.
Function
The throttle valve activation occurs via an electric motor (throttle drive) in the throttle valve control module. This is operated by Engine Control Module (ECM) according to specifications from both Throttle Position (TP) Sensor G79 and Accelerator Pedal Position Sensor 2 G185.
Components of Throttle Valve Control Module J338
- Throttle Drive (for Electronic Power Control (EPC)) G186
- Throttle Drive Angle Sensor 1 (for Electronic Power Control (EPC)) G187
- Throttle Drive Angle Sensor 2 (for Electronic Power Control (EPC)) G188
Special tools, testers and auxiliary items required
- Multimeter VAG1526 or Multimeter VAG1715
- Connector test kit VAG1594
- Wiring diagram
Test Prerequisites
- The respective fuses of Engine Control Module (ECM) J623 must be OK: --> Electrical Wiring Diagrams, Troubleshooting and Component Locations
- Battery voltage must be at least 11.5 Volts.
- All electrical consumers such as, lights and rear window defroster must be switched off.
- Parking brake must be engaged or else daylight driving lights will be switched on.
- If vehicle is equipped with an A/C system, it must be 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 --> «Diagnostic Mode 01 - Read Current System Data»(/audi/a8/d3-2005-2007/remont/cooling-fan/#42l-v8-5v-generic-scan-tool-engine-codes-bfm__diagnostic-mode-01-read-current) ; PID 5, Coolant temperature.
Function Test
- Connect diagnostic tester --> «Diagnostic Tester, Connecting»(/audi/a8/d3-2005-2007/remont/cooling-fan/#42l-v8-5v-generic-scan-tool-engine-codes-bfm__diagnostic-tester-connecting) .
- Switch ignition on.
- Under address word 33, select "Diagnostic mode 1: Checking measured values."
- Select the measuring value "PID 17: Throttle valve position (absolute)."
- Check specified value of throttle valve position (absolute) at idle stop
| PID | Diagnostic text | Specified value | ||||
|---|---|---|---|---|---|---|
| 17 | Throttle valve position (absolute) | |||||
| Idle stop | 8.0 to 18.0% | |||||
- Slowly depress accelerator pedal up to Wide Open Throttle (WOT) stop while observing the percentage display.
Specified value: The percentage display must increase uniformly
- Check specified value of throttle valve position (absolute) at Wide Open Throttle (WOT) stop
| PID | Diagnostic text | Specified value | ||||
|---|---|---|---|---|---|---|
| 17 | Throttle valve position (absolute) | |||||
| Wide Open Throttle (WOT) stop | 84.0 to 97.0% | |||||
- End diagnosis and switch ignition off.
If specified values are not reached, check voltage supply.
- Pull connector off throttle valve control module.
- Switch ignition on.
- Connect multimeter to the following connector terminals for voltage measurement
| 6-pin connector at wiring harness, terminal | Specified value |
|---|---|
| 2 + Ground (GND) | About 5 V |
| 2 + 6 | About 5 V |
If specified values are obtained, also check signal wires and activation wires of throttle valve control module.
If specified values are not obtained
Check wire connections from Engine Control Module (ECM) to throttle valve control module.
- Pull connector off throttle valve control module.
- Connect test box VAG1598/31 to wiring harness of Engine Control Module (ECM) --> «Wire and Component Test at Engine Control Module using VAG 1598/31»(/audi/a8/d3-2005-2007/remont/cooling-fan/#42l-v8-5v-generic-scan-tool-engine-codes-bfm) .
The following wire connections must be checked for short circuit to B+, Ground (GND) and for open circuit
| 6-pin connector at wiring harness, terminal | Test box VAG1598/31 , socket |
|---|---|
| 1 | 92 |
| 2 | 83 |
| 3 | 117 |
| 4 | 84 |
| 5 | 118 |
| 6 | 91 |
- Repair open circuit in wiring or short circuit if necessary. --> Electrical Wiring Diagrams, Troubleshooting and Component Locations
If no malfunctions are found in wires
- Replace throttle valve control module.
- Read readiness code --> «Readiness Code, Reading»(/audi/a8/d3-2005-2007/remont/cooling-fan/#42l-v8-5v-generic-scan-tool-engine-codes-bfm__readiness-code-reading) . If DTC memory was erased, readiness code must be generated again --> «Readiness Code, Generating»(/audi/a8/d3-2005-2007/remont/cooling-fan/#42l-v8-5v-generic-scan-tool-engine-codes-bfm__readiness-code-generating) .