C0642 Diagnostic Trouble Code

C0642 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 C0642 diagnostic trouble code may include:

Lack of power
Faulty O2 Sensor
Poor acceleration
Engine surge

Possible Causes :

Rarely - faulty Powertrain Control Module (PCM-programming required after replacement)
Rough running engine due to misfiring plugs. Many engines have misfire codes to indicate the cylinder effected, such as P0307 for number 7.
A large vacuum leak would cause a massive amount of un-metered air to enter the intake manifold resulting in an overly lean mixture.

Repair Processes :

With the valve disconnected, the red voltmeter lead should be attached to the IMRC valve power wire and the black voltmeter lead connected to ground. Now, clear the codes and test-drive the vehicle to see if the code is reset.

Process Tips

Diagnostic trouble code C0642 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 C0642.

Fortunately, C0642 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.

C0642 Trouble Code For Specific Cars

C0642 Hyundai Concept SCP (J1850) Communication Bus Fault
C0642 Opel Zafira B Door Lock Cylinder Circuit Short To Battery
C0642 Pontiac Firehawk Exhaust Valve Control Solenoid C ircuit High (Bank 1)
C0642 Nissan R300 Crankshaft Position Sensor A Circuit Low Input
C0642 Volvo C70 SCP (J1850) Invalid or Missing Data for Engine RPM
C0642 Mazda Axela Transmission Transfer Case Contact Plate Power Short To Ground
C0642 Holden Hq Power Door Unlock Circuit Failure