Transmission Position Sensor/Switch: Testing and Inspection

Engine Control Module (ECM) -J248- receives a gear change signal from the Transmission Control Module (TCM) via the CAN-Bus wire. The engine Engine Control Module (ECM) briefly reduces the amount of fuel injected. This reduces torque and gear change jolt.

Special tools and equipment
- Scan Tool (ST) V.A.G 1551/1552 with cable V.A.G 1551/3
- VAG 1598/22 Test box (through my 1999)
- VAG 1598/31 (from my 2000)
- Digital multimeter US 1119 (Fluke 83 or equivalent)
- VAG 1594 Adapter kit
- Wiring diagram

Test sequence
- Connect Scan Tool V.A.G 1551/1552 refer to "On Board Diagnostic II/VAG 1551/VAS 5051 Scan Tool, Connecting" under "Fuel Delivery and Air Induction/Testing and Inspection".
- Start engine and let idle
- Press -0- and -1 - to select Address word 01: "Engine electronics"


WARNING!
If test equipment is operated from the front seat and vehicle is involved in an accident injury may result. Secure Scan Tool to rear seat.


Indicated on display:


Rapid data transfer HELP
Select function XX


- Press buttons -0- and -8- for "Read measured value block" and confirm with -Q- button.

Indicated on display:


Read measured value block HELP
Input display group number XXX


- Press buttons -0-, -0- and -9- for "Display group number 9" and confirm with -Q- button.
- Test drive with a 2nd person to observe display.

Observe safety precautions when driving road test.

- Observe display in field 3 when changing to 2nd gear:


Read measured value block 9 ->
3240 rpm 4.8 mg/h 50.0 mg/h


Specification: Briefly less than 51 mg/h


NOTE: Data transfer is slow, it is possible specification display is delayed for a few moments.


- Press -> button.
- Press buttons -0- and -6- for "End output" and confirm with -Q- button.
- Switch off ignition.

If specification is not obtained:
- Check CAN-bus