Heated Oxygen Sensor, Engine Code BEW, Checking
Applies to Engine Code (BEW) only
Oxygen Sensor (O2S) Heater -Z19- is part of Heated Oxygen Sensor (HO2S) -G39- and cannot be serviced separately.
When servicing terminals in the electrical harness connector of Heated Oxygen Sensor (HO2S) -G39-, use only gold-plated terminals.
Special tools and workshop equipment required
- Multimeter.
- Wiring diagram.
Test requirements
- Fuse -S13- 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.
Test procedure
-- Perform a preliminary check to verify the customers complaint. Refer to PRELIMINARY CHECK .
Start diagnosis
-- Vehicle must be raised to access Heated Oxygen Sensor (HO2S) -G39-
-- Access to Heated Oxygen Sensor is beneath synthetic cover at vehicle floor.
-- Disconnect the Heated Oxygen Sensor (HO2S) -G39- electrical harness connector.
Checking internal resistance
-- Using a multimeter, check the Heated Oxygen Sensor (HO2S) -G39- terminals 3 to 4 for resistance.
Specified value: 2.5 to 10.0 Ω (at approx. 20° C)
If the specification was not obtained:
-- Replace Heated Oxygen Sensor (HO2S) -G39-. Refer to EXHAUST MANIFOLD, FRONT EXHAUST PIPE WITH THREE WAY CATALYTIC CONVERTER AND ATTACHMENTS ASSEMBLY OVERVIEW, ENGINES WITH 2 OXYGEN SENSORS or refer to EXHAUST MANIFOLD, FRONT EXHAUST PIPE WITH THREE WAY CATALYTIC CONVERTER AND ATTACHMENTS ASSEMBLY OVERVIEW, ENGINES WITH 3 OXYGEN SENSORS .
If the specification was obtained:
Checking voltage supply
Crank the engine.
-- Using a multimeter, check the Heated Oxygen Sensor (HO2S) -G39- electrical harness connector terminal 4 to Ground (GND) for voltage.
| Heated Oxygen Sensor (HO2S) -G39- electrical harness connector terminal | Measure to |
|---|---|
| 4 | Ground (GND) |
Specified value: Battery voltage.
Switch the ignition off.
If the specification was not obtained:
-- Check the wiring from the Heated Oxygen Sensor (HO2S) -G39- electrical harness connector terminal 4 to the Power Supply Relay (terminal 30, B+) -J317- socket 2/30 for an open circuit, a short circuit to Battery (+), or Ground (GND).
-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
-- If necessary, repair the faulty wiring connection.
If the specification was obtained:
Checking Ground (GND) activation
If the manufacturers test box is being used, perform the following step.
-- Install the test box.
If the manufacturers test box is not being used, perform the following step.
-- Remove the Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) -J248-. Refer to ENGINE CONTROL MODULE, REPLACING .
-- Using a multimeter, check the Heated Oxygen Sensor (HO2S) -G39- electrical harness connector to the Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) -J248- electrical harness connector T94 for resistance.
| Heated Oxygen Sensor (HO2S) -G39- electrical harness connector terminal | Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) -J248- electrical connector T94 terminal or test box socket |
|---|---|
| 1 | 32 |
| 2 | 10 |
| 3 | 51 |
| 5 | 54 |
| 6 | 77 |
Specified value: 1.5 Ω.
If the specification was not obtained:
-- Check the wiring for an open circuit, a short circuit to Battery positive (+) or Ground (GND).
-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
-- If necessary, repair the wiring connection.
If the specification was obtained:
-- Erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
-- Perform a road test to verify repair.
If the DTC does not return:
Repair complete, Generate readiness code. Refer to READINESS CODE .
-- End diagnosis.
If the DTC returns and no malfunction is found in the wiring and voltage supply was OK:
-- Replace the Diesel Direct Fuel Injection (DFI) Engine Control Module (ECM) -J248-. Refer to ENGINE CONTROL MODULE, REPLACING .
Assembly is performed in the reverse order of the removal, note the following:
Final procedures
After repair work, the following work steps must be performed in the following sequence:
- Check the DTC memory. Refer to DIAGNOSTIC MODE 03 - READ DTC MEMORY .
- If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
- If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .
End of Diagnosis