Signal Too Low - Permanent Fault

ECM-280A FRONT HEATED OXYGEN SENSOR (HO2S), FAULTY SIGNAL
SIGNAL TO LOW - PERMANENT FAULT

Checking connector, wiring and components




CAUTION!
Do not apply rust solvent spray or grease to the Heated Oxygen Sensor (HO2S) connector.

Check Heated Oxygen Sensor (HO2S) connector for contact resistance and oxidation according to [1][2]Checking Wiring and Terminals. Permanent Fault

Check signal cable (-) between Heated Oxygen Sensor (HO2S) # 5 and control module # A42 (# A42) and power supply for calibration between Heated Oxygen Sensor (HO2S) # 2 and control module # A28 (# A28) for an open-circuit according to [1][2]Checking Wiring and Terminals. Permanent Fault

Check calibration current power cable between Heated Oxygen Sensor (HO2S) # 2 and control module # A28 (# A28) and power supply for pump current between Heated Oxygen Sensor (HO2S) # 6 and control module # A24 (# A24) for a short-circuit to each other according to [1][2]Checking Wiring and Terminals. Permanent Fault

If the connector and cables are OK try a new Heated Oxygen Sensor (HO2S).

Remedy as necessary.

Other information
- Connecting the breakout box/accessing the control module Connecting the Breakout Box (ECM)
- To access/replace the heated oxygen sensor (HO2S), Adapter Wiring Switch, Replacing
- For information about signals, see Diagnostic Parameters and Pinout Values. Signal Description, ME7, B5XX4T


Verification



Hint: After carrying out the repair, check that the fault has been remedied.

- Ignition off.
- Reconnect connectors, reinstall components.
- Test drive the car according to the TRIP schedule, Monitors, Trips, Drive Cycles and Readiness Codes

NOTE: After test driving the engine should not be turned off. The test drive must be carried out again.

Connect VIDA again and read out the front Heated Oxygen Sensor (HO2S) Diagnostic Trouble Code (DTC) status.
The value should be higher than 1.0.

Is the value higher than 1.0?
Yes - Testing Complete.
No - Continue below.


Fault-tracing information
The fault should have been detected and remedied. As this is not the case fault-tracing has failed. Exit fault tracing for this diagnostic trouble code (DTC) or make another attempt.