C1042 Diagnostic Trouble Code

C1042 is a kind of OBD-II Diagnostic C-Chassis Diagnostic Trouble Code.

It is considered generic because it applies to all makes and models of vehicles, although specific repair steps may be different depending on your car model.

Symptoms

Symptoms of a C1042 diagnostic trouble code may include:

Fuel pressure too high
Diminished fuel efficiency
Rich or lean exhaust
If the DPF is not cleared the ECU will revert to the "Limp Home Mode" until the situation is corrected

Possible Causes :

Fuel with a large percentage of sulfur will clog the DPF quickly
The Mass Airflow sensor will also cause this problem. Mass Airflow circuit malfunction.
Faulty IMRC actuator relay (if equipped)

Repair Processes :

Find out what kind of system you have and verify that voltage to the fuel level sensor is present at the fuel pump wiring harness. Oxygen sensors signal the engine management computer the amount of oxygen present in the exhaust, which is used in determining and controlling the fuel ratio. Use the DVOM to test resistance and continuity on all system circuits if actuator and sensor resistance levels are in compliance with manufacturer's specifications.

Process Tips

Diagnostic trouble code C1042 is not difficult to diagnose and repair. Thus, it always pays to have a qualified technician to look after your vehicle should this error code arise.

Diagnosing this code requires the engine to be in good running shape, without unmetered air entering the engine. If other codes that relates to misfiring condition, lean running or air entering the engine is present, then you must first fix those error codes before C1042.

Fortunately, C1042 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

C1042 Trouble Code For Specific Cars

C1042 Seat Leon Injector Control Pressure Sensor Above / Below Desired
C1042 Dkw F91 Idle Switch (Electric Control Throttle) Circuit Malfunction
C1042 Alvis Silver Air Bypass Valve Circuit Malfunction
C1042 Hotchkiss Anjou Ride Control LF Shock Actuator Circuit Short To Ground
C1042 Mazda Mazdaspeed Turbocharger Boost Sensor A Circuit Range/Performance
C1042 Triumph Italia PATS Is Disabled (Check Link Between PATS And Transponder)
C1042 Abarth Renault Fregate A/C pressure sensor circuit voltage high