Engine Speed Sensor, Checking

Engine Speed Sensor, Checking

Observe all safety precautions: => [ Safety Precautions ] Safety Precautions

View clean working conditions: => [ Clean Working Conditions ] Clean Working Conditions

Prior to repair work, perform a preliminary check to verify the condition. Refer to => [ Preliminary Check ] Preliminary Check.

• 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 Engine Control Module (ECM) (J623) 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 connections between engine/transmission/chassis OK.

• Ignition switched Off.

Test procedure

- Perform a preliminary check to verify the customers complaint. Refer to => [ Preliminary Check ] Preliminary Check

Start diagnosis

- Connect the scan tool.

- Start the engine and allow it to idle.

- Using the scan tool, check the engine speed:






- Switch ignition OFF.

If the specified value was obtained:

- Fault is intermittent. Check harness connectors and terminals for loose connections or poor terminal contact.

If the specified value was Not obtained:

- Remove the engine cover.

- Disconnect the Engine Speed Sensor (G28) electrical harness connector.

- Switch the ignition On.

- Using a multimeter, Check the Engine Speed Sensor (G28) electrical harness connector terminals 1 to 3 for voltage.

Specified value: near 5.01 V

- Using a multimeter, Check the Engine Speed Sensor (G28) electrical harness connector terminals 2 to 3 for voltage.

Specified value: near 4.92 V

- Switch the ignition Off.

If all of the specified values were obtained:

- Replace the Engine Speed Sensor (G28). Refer to the Repair Information.

If any of the specified values were Not obtained:

Checking wiring

- Remove the Engine Control Module (ECM) (J623). Refer to the Repair Information.

- Using a multimeter, Check the Engine Speed Sensor (G28) electrical harness connector to the Engine Control Module (ECM) electrical harness connector T105 for an open circuit.






Specified value: 1.5 ohms Max.

If any specified values were Not obtained:

- Check the wiring connection for an open circuit, high resistance, short circuit to Battery (+) or Ground.

- Check the wiring connection for damage, corrosion, loose or broken terminals.

- If necessary, repair the faulty wiring connection.

If no malfunction is found in the wiring and voltage supply was Not OK:

- Replace the Engine Control Module (ECM) (J623). Refer to the Repair Information.

- Install the engine cover with air filter. Refer to the Repair Information.

Final procedures

After the repair work, the following work steps must be performed in the following sequence:

1. Check the DTC memory. Refer to => [ Diagnostic Mode 03 - Read DTC Memory ] Diagnostic Modes 01 - 09.

2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09.

3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code ] Monitors, Trips, Drive Cycles and Readiness Codes.