Signal Too Low - Permanent Fault

ECM-3420 KNOCK SENSOR (KS) REAR
SIGNAL TOO LOW - PERMANENT FAULT

Checking wiring and components



Check Knock Sensor (KS) connector for contact resistance and oxidation according to [1][2]Checking Wiring and Terminals. Intermittent Faults

Check the signal cable between Knock Sensor (KS) # 3 and control module # A45 (# A45) and the ground lead between Knock Sensor (KS) # 4 and control module # A67 (# B7) for an open-circuit according to [1][2]Checking Wiring and Terminals. Intermittent Faults and for a short-circuit to ground according to [1][2]Checking Wiring and Terminals. Intermittent Faults

Check that the Knock Sensor (KS) is tightened to the correct torque.

Remedy as necessary.

Other information
- Connecting the breakout box/accessing the control module Connecting the Breakout Box (ECM)
- To access/replace the knock sensor (KS), Knock Sensor, Replacing
- For information about signals, see Diagnostic Parameters and Pinout Values. Signal Description, ME7, B5XX4T


Checking knock sensor (KS) signal



- Ignition off
- Reinstall components, reconnect connectors etc.
- Start engine and run to normal operating temperature.
- Rev the engine to 3500 rpm and Read the value of the Knock Sensor (KS) signal.

The value should be between 2 and 6.
If the value is now OK it means that the cause of the fault has been loose connections in connector.

Other information
- Connecting the breakout box/accessing the control module Connecting the Breakout Box (ECM)
- For information about signals, see Diagnostic Parameters and Pinout Values. Signal Description, ME7, B5XX4T

Is the value between 2 and 6?
Yes - Testing complete.
No - Continue below.


Replacing component



Replace Knock Sensor (KS) according to Knock Sensor, Replacing



Verification



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

- Ignition off.
- Reconnect the connectors, reinstall components etc.
- Start engine and run to normal operating temperature.
- Rev the engine to 3500 rpm and Read the value of the Knock Sensor (KS) signal.

Is the value between 2-6?
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.