Diagnostic trouble code (DTC) information CEM-3F90
Condition
Central electronic module (CEM) checks the fuel pump relay, and activates it, when an approved check has been made by the system for Immobilizer. The fuel pump relay is located internally in the Central electronic module (CEM). The fuel pump relay sends voltage feed to the fuel pump when the relay is activated.
If Central electronic module (CEM) detects that the voltage on the output to the fuel pump is too low, the diagnostic trouble code is generated.
The diagnostic trouble code (DTC) can be diagnosed when the fuel pump is activated.
When troubleshooting, the fuel pump may not be supplied with voltage by an external power source without first disconnecting the connector to the Central electronic module (CEM). If the connector is not loosened and the fuel pump is supplied with voltage, this can lead to failure of an internal ground conductor in the Central electronic module (CEM). In turn, this can lead to a number of other malfunctions in the vehicle and that Central electronic module (CEM) must be replaced.
The following applies to vehicles with fuel pump module (PEM):
Central electronic module (CEM) checks the voltage feed to the fuel pump module. The Central electronic module (CEM) activates the voltage supply to the fuel pump control module after the checks carried out by the function for the immobilizer have been approved.
If Central electronic module (CEM) detects that the voltage on the output to the fuel pump module (PEM) is too low, the diagnostic trouble code is generated.
The diagnostic trouble code (DTC) can be diagnosed when the fuel pump is activated.
Substitute Value
- None.
Possible Source
- Damaged power supply fuse.
- Open circuit on cables for voltage feed between fuse box engine compartment and Central electronic module (CEM).
- The cable for voltage feed between Central electronic module (CEM) and fuel pump module (PEM)/fuel pump is short-circuited to ground.
Fault symptom[s]
- The engine does not start.