Signal Too Low

ECM-8400 5 VOLT POWER SUPPLY
SIGNAL TOO LOW

Reading Diagnostic trouble code (DTC) status ECM-8400



Note! When Reading the Diagnostic trouble code (DTC) status, other stored diagnostic trouble codes (DTCs) and their status will be listed.

- Read the Diagnostic trouble code (DTC) status. Check the status of the relevant Diagnostic Trouble Code (DTC).

Was the status of the relevant Diagnostic Trouble Code (DTC) displayed as permanent?
Yes - Continue below.
No - Signal Too Low - Intermittent Fault


Checking cables



Note! The 5 volt supply for the various components is common internally in the control module. Therefore the control module cannot identify which of the outputs are short-circuited to ground. Consequently all the affected outputs must be checked for a short-circuit to ground.

Check cables between
- control module #A57 and camshaft position (CMP) sensor #1
- control module #A58 and manifold absolute pressure (MAP) sensor #3
- control module #A58 and air conditioning (A/C) pressure sensor #3
- control module #B10 and fuel tank pressure sensor #3
for a short-circuit to ground according to [1][2]Checking Wiring and Terminals. Permanent Fault

Remedy as necessary.

Other information
- Connecting the breakout box/accessing the control module, Connecting the Breakout Box (ECM)
- To access/replace the control module, Engine Control Module (ECM), Replacing
- To access/replace the camshaft position (CMP) sensor, Camshaft Position Sensor (CMP), Replacing
- To access/replace the mass air flow (MAF) sensor, Mass Air Flow (MAF) Sensor, Replacing
- To access/replace air conditioning (A/C) pressure sensor, Pressure Switch/Pressostat, Replacing
- To access/replace the fuel tank pressure sensor, Fuel Tank Pressure Sensor, Replacing
- 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.

Read the 5 volt power supply to the sensors.

Is the voltage OK?
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.