Faulty Signal

ECM-820A SYSTEM RELAY
FAULTY SIGNAL

Checking component



- Ignition off.
- Remove the system relay.

Check if there is an open-circuit in the system relay # 30(1) and # 87(3) according to [1][2]Checking Wiring and Terminals. Permanent Fault

Hint: When the relay is not routed their should be an open circuit between the system relay # 30(1) and # 87(3). If there is not an open-circuit the relay is defective.

Check signal cable between engine control module (ECM) # 85(4) and brake pedal sensor # B38 (# B50) for a short-circuit to ground according to [1][2]Checking Wiring and Terminals. Permanent Fault

Remedy as necessary.

Other information:
- To connect the breakout box, Connecting the Breakout Box (ECM)
- To access/replace the system relay, Replacing Relay In the Main Fuse Box
- The system relay coil # 86(2) is connected to k1:30 and # 87(3) and is connected to the engine control module (ECM) connector # B38 (# B50) and is actively low.
- For information about signals, Pinout Values and Diagnostic Parameters

Has the fault been remedied?
Yes - Skip to "Verification"
No - Continue below.


Checking power cable



Check if there is an open-circuit in the system relay base # 87(3). The system relay base # 87(3) should be without voltage.

If there is voltage in the system relay base # 87(3), check the terminals and junctions from the base # 87(3) (see wiring diagram) for a short-circuit to supply voltage according to [1][2]Checking Wiring and Terminals. Permanent Fault

Remedy as necessary.

Other information:
- To connect the breakout box, Connecting the Breakout Box (ECM)
- To access/replace the system relay, Replacing Relay In the Main Fuse Box
- The system relay # 30(1) is connected to k1:30 and # 87(3) is the output.
- For information about signals, Pinout Values and Diagnostic Parameters


Verification



Hint: After carrying out the repair, check that the fault has been remedied.
- Ignition off.
- Reinstall connectors, components etc.
- Ignition on.
- Disconnect the connector from mass air flow (MAF) sensor.
- Check the voltage of the mass air flow (MAF) sensor # 1. It should be approximately Ubat.
- Ignition off.

Check the system relay when it "releases" (approximately 2 minutes after ignition off).

Check the voltage on mass air flow (MAF) sensor # 1. It should be 0 V when the system relay is not drawing on it.

Is the mass air flow (MAF) sensor # 1 voltage 0 Volts?
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.