Engine Speed Sensor, Checking: Notes
Use only gold-plated terminals when servicing terminals in the electrical harness connector of the Engine Speed (RPM) Sensor -G28-.
Special tools and workshop equipment 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.
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.
Test procedure
-- Perform a preliminary check to verify the customers complaint. Refer to PRELIMINARY CHECK
Start diagnosis
-- Disconnect the Engine Speed (RPM) Sensor -G28- electrical harness connector.
-- Switch the ignition On.
-- Using a Multimeter, Check the Engine Control Module (ECM) - J623 - electrical harness connector terminals 1 to 3 for voltage.
Specified value: about 5.0 V
-- Switch the ignition Off.
Continue test according to the following table:
| Value | Cause | Test |
|---|---|---|
| If the specified value was not obtained: | Open or shorted circuit | Checking wiring |
| If the specified value was obtained: | Check reference signal circuit | Checking Activation |