Section 5 - Evaluating Results and Repairing
5. EVALUATING RESULTS AND REPAIRING
5.1 Throttle Position (TP) sensor (PID 2461)
If customer complaint or the road test indicates:
^ Stalling/cutting out
^ Erratic on measuring value block 5 If terminals are not gold plated:
Replace TP Sensor
Check wire connections to the TP Sensor and look for and correct the following:
^ Corrosion
^ Low tension on the connectors
^ Broken wires (wiggle)
^ Poor crimps
^ Terminals not locked in
^ Apply contact enhancer
Drive the vehicle under the same conditions that the customer has experienced the complaint. as stated in the questionnaire.
While driving observe Function 08, Display Group 05, Channel 2 (Second technician Is necessary)
Drive at a constant speed, slightly accelerating and decelerating one degree at a time.
Try to observe an erratic change in throttle angle. The angle will abruptly change to a lower value. If the value drops very low you will experience a temporary fuel shutoff or a slight miss or hesitation
If the reading is erratic while driving at a constant speed, print Channel 2 several times to record fluctuations, and:
- Replace the TP Sensor
5.2 KNOCK SENSOR (PID 2872)
If you have a malfunction, the customer complaint1 or the road test indicates:
- Poor gas mileage
- Lack of power
- Poor acceleration
Then check and repair if required the knock sensor connections for:
- Corrosion
- Low tension on the connectors
- Broken wires (wiggle I)
- Poor crimps
- Terminals not locked in
- Apply contact enhancer
Check knock sensor terminals for correct plating material:
Note:
For more information refer to Technical Bulletin 92-5, Group 28, dated December 31, 1992.
Replacement knock sensors have gold plated terminals. Earlier original equipment sensors have alloy plated terminals.
Both the male and female terminals of the knock sensor connection must be the same material. not, they must be replaced.
Always use a crimping tool which forms a "W" crimp when replacing wiring connectors.
Note:
If replacing older version knock sensor with new version with gold plated terminals, the female connector housing may also have to be replaced. Refer to Technical Bulletin 9O-03, Group 28, dated October 31, 1990.
Check knock sensor wiring at knock sensor and at the Engine Control Module (ECM). Wire should match diagram.
Terminal assignment should be verified at each end. It is possible that a previous repair was attempted and some terminals were mispositioned.
Shielded wire (black) must be connected terminal 8 of connector for ECM engine control module (J 169) and to terminal T3g/3 of connector for knock sensor (G 61)
White wire must be connected to terminal 29 of connector for ECM (J 169) and to terminal T3g/1 of connector for knock sensor (G 61)
Yellow wire must be connected to terminal 27 connector for engine control module (J 169) and to terminal T3g/2 of connector for knock sensor (G 61)
Check knock sensor installation torque Loosen knock sensor bolt and torque to 20 to Nm (engine cold) (15 to 18 ft/lb)
Note:
Be sure to use a torque wrench that reads accurately in this lower range
Note:
Check for loose engine components, they can affect the knock sensor signal
Road test to verify that the problem has been corrected.
5.3 IDLE AIR CONTROL VALVE (IAC VALVE) (PID 2481)
If customer complaint or the road test Indicates:
- Low/high idle
- Stalling/Surging idle
Then check and repair if required the IAC Valve connections for:
- Corrosion
- Low tension on the connectors
- Broken wires (wiggle!)
- Poor crimps
- Terminals not locked in
- Apply contact enhancer
Check mA-reading to the IAC Valve. Use harness VW 1315A/2.
The mA-reading should be between:
^ 450...550 mA
The idle speed should be between:
^ 750.850 mm
If the idle speed surges excessively adjust the Idle screw out one to two turns. Confirm that the mA's are still between 450...550 mA
Reseal the screw after adjusting
If the mA-reading is within or below the normal range, but the idle speed is incorrect, check for a sticking IAC Valve.
If the IAC-Valve is sticking and by tapping the IAC Valve the Idle speed returns to normal, contact the VW Technician Helpline.
5.4 OTHER-PROBLEMS Mass Air Flow sensor (PID 2445)
Connections for:
- Corrosion
- Low tension on the connectors
- Broken wires (wiggle!)
- Poor crimps
- Terminals not locked in
- Apply contact enhancer
If customer complaint or the road test indicates:
- Cold start-Driveaway-Lack of power Contact the VW Technician Helpline