Signal Too High

ECM-280A FRONT HEATED OXYGEN SENSOR (HO2S), FAULTY SIGNAL
SIGNAL TO HIGH

Checking for air leakage in the exhaust system



Check for air leakage according to Checking For Air Leakage In the Exhaust System

Was there any air leakage?
Yes - Skip to "Verification".
No - Continue below


Checking wiring and components




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

Check signal cable (+) between Heated Oxygen Sensor (HO2S) # 1 and control module # A41 (# A41). Check the cable for pump current between Heated Oxygen Sensor (HO2S) # 6 and control module # A24 (# A24). Check for a short circuit to supply voltage.

Check signal cable (+) between Heated Oxygen Sensor (HO2S) # 1 and control module # A41 (# A41). Check the cable for pump current between Heated Oxygen Sensor (HO2S) # 6 and control module # A24 (# A24). Check for a short-circuit to ground.

If wiring is OK, try another 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 difference between front and rear oxygen sensors (HO2S).
The value should be lower than ±0.01

Is the value lower than ±0.01?
Yes - Testing Complete.
No - Continue below.


Checking wiring and components




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

Hint: The fault may be caused by a fault in the circuit for the rear heated oxygen sensor (HO2S)

Check the rear heated oxygen sensor (HO2S) connector. Check for contact resistance and oxidation.

Check signal cable (+) between Heated Oxygen Sensor (HO2S) terminal # 4 and control module # A61 (# B1). Check signal cable (+) between Heated Oxygen Sensor (HO2S) # 3 and control module # A62 (# B2). Check for an open-cicuit. Check for a short-circuit to ground. Check for a short-circuit to ground.

If wiring is OK, try another 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
- [1][2]Checking Wiring and Terminals


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.