Engine Speed (RPM) Sensor G28, Checking
Engine Speed (RPM) Sensor G28, checking
Note: Use only gold-plated terminals when servicing terminals in the electrical harness connector of the Engine Speed (RPM) Sensor G28.
Special tools, testers and auxiliary items required
- Multimeter.
- Wiring diagram.
Test requirements
The MFI Engine Control Module (ECM) J192 fuses OK.
Battery voltage at least 12.5 volts.
All electrical consumers such as, lights and rear window defroster, switched off.
Vehicles with automatic transmission, shift selector lever into position "P" or "N".
A/C switched off.
Ground (GND) connections between engine/transmission/chassis OK.
Ignition switched off.
Function
The Engine Speed (RPM) Sensor G28 detects RPM and reference marks. Without an engine speed signal, the engine will not start. If the engine speed signal fails while the engine is running, the engine will stop immediately.
Function test
- Connect the scan tool.
- Switch the ignition on.
- Using the scan tool, check the engine speed:
Diagnostic text Specified value
Engine rotations per minute (RPM) Idle speed
- End diagnosis and switch ignition off.
If the specified value was not obtained:
Test procedure
Perform a preliminary check to verify the customers complaint.
Note: The Engine Speed (RPM) Sensor G28 adjustment is preset at the factory and should be moved unless the Engine Speed (RPM) Sensor G28 bracket has been moved.
- Check the Engine Speed (RPM) Sensor G28 adjustment.
Start diagnosis
- Disconnect the black Engine Speed (RPM) Sensor G28 electrical harness connector -3-.
Checking internal resistance
- Using a multimeter, check the Engine Speed (RPM) Sensor G28 terminals 1 to 2 for resistance.
Specified value: 730 to 1000 ohms
If the specified value was not obtained:
- Replace the Engine Speed (RPM) Sensor G28.
If the specified value was not obtained:
- Using a multimeter, check the Engine Speed (RPM) Sensor G28 terminals 1 to 3 and 2 to 3 for short circuits.
Specified value: (infinity)
If any of the specified values are not obtained:
- Replace the Engine Speed (RPM) Sensor G28.
If the specified values are obtained:
Checking wiring
If the manufacturers test box is being used. Perform the following step. Install the Adapter (96pin) OBDII VAG1598/19.
If the manufacturers test box is not being used. Perform the following step.
- Remove the MFI Engine Control Module (ECM) J192.
- Using a Multimeter, check the Engine Speed (RPM) Sensor G28 electrical harness connector terminals to the MFI Engine Control Module (ECM) J192 electrical harness connector terminals for an open circuit.
Engine Speed (RPM Sensor G28 MFI Engine Control Module (ECM) J192
electrical harness connector electrical harness connector A or test box
terminals socket terminals
1 A11
2 A9
Specified value: 1.5 ohms Max.
If the specification was not obtained:
- Check the wiring for a short circuit to each other or Battery (+).
- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
- If necessary, repair the faulty wiring connection.
If no malfunction is detected in the wiring:
- Using a Multimeter, check the Engine Speed (RPM) Sensor G28 electrical harness connector terminal 3 to Ground (GND) connection in engine compartment wiring harness for an open circuit.
Specified value: 1.5 ohms Max.
If the specification was not obtained:
- Check the wiring for a short circuit to each other or Battery (+).
- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
- If necessary, repair the faulty wiring connection.
If no malfunction is detected in the wiring:
- Remove the Starter and check the ring gear for broken or chipped teeth. Replace the ring gear if damaged.
If the ring gear is OK and no damage is found:
- 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 was Engine Speed (RPM) Sensor G28 OK:
- Replace the MFI Engine Control Module (ECM) J192.
- 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 diagnosis.
Engine Speed (RPM) Sensor G28, adjusting
Special tools, testers and auxiliary items required
- Crankshaft Holder 3242 or equivalent.
- Rpm Sensor Adjustment Tool 3308 or equivalent.
Adjustment procedure
Note: The Engine Speed (RPM) Sensor G28 adjustment is preset at the factory and should be moved unless the Engine Speed (RPM) Sensor G28 bracket screws have been loosened and has been moved.
- Rotate the crankshaft -B- to Top Dead Center (TDC) -A-.
- Remove the Crankshaft Position (CKP) Sensor G4 from the left side of the cylinder block.
Crankshaft Holder 3242 Shown In Installed Position:
- Install the Crankshaft Holder 3242 or equivalent into the Top Dead Center (TDC) opening in the left side of the cylinder block and tighten.
Note: The Top Dead Center (TDC) opening can be seen and felt with a finger.
- Remove the Engine Speed (RPM) Sensor G28 and heat shield.
- Loosen the Engine Speed (RPM) Sensor G28 bracket screws.
- Install the Rpm Sensor Adjustment Tool 3308 or equivalent into the Engine Speed (RPM) Sensor G28 bracket.
Note: The Rpm Sensor Adjustment Tool 3308 must lock into the ring gear.
- Tighten the Engine Speed (RPM) Sensor G28 bracket screws.
- Remove the Rpm Sensor Adjustment Tool 3308 from the Engine Speed (RPM) Sensor G28 bracket.
- Install the Engine Speed (RPM) Sensor G28 and heat shield.
- Remove the Crankshaft Holder 3242 from the Top Dead Center (TDC) opening in the left side of the cylinder block.
- Install the Crankshaft Position (CKP) Sensor G4.