C251C Pontiac Tempest OBD Code

OBD/2 C251C error code description and symptoms.

Catalytic converters must be warm before they can work properly. On a cold start the PCM provides a rich mixture to keep the cold engine running.
All that extra fuel goes into the catalytic converter. But the exhaust isn't very hot, because, ah, the engine is pretty cold. GM has employed several strategies to fire up the catalytic converter quicker and reduce cold start emissions. One way is to use a secondary air pump that pumps outside air directly into the catalytic converter.

At this point we are assuming that the fuses and relays are good. You will need to locate the PCM/TCM and the power input signal circuit using your vehicle information source. Unplug the connector from the PCM/TCM, place the ignition switch in the ON position, and probe the appropriate circuit with the positive test lead of the DVOM.

C251C Pontiac Tempest Error Code Repair Process :

If your vehicle failed a C251C test and the C251C Check Engine Light is NOT on, chances are you have a problem with the OBDII system, a burned out MIL lamp, or a faulty catalytic converter. The converter is essentially an afterburner that cleans up the exhaust after it exits the engine. The OBDII system uses transmission neutral safety switch short circuit to battery a ownstream oxygen sensor to monitor the efficiency of the converter, and it should detect a drop in converter efficiency if the converter has been contaminated or is failing (ignition misfiring, leaky exhaust valves, and oil burning can all damage the converter). What you want to look transmission neutral safety switch short circuit to battery: Any conditions that might cause ignition misfire, an overly rich or lean fuel condition, or loss of compression. Use your OBD Express DIY to look at the oxygen sensor outputs, coolant temperature, airflow, calculated engine load, and inlet air temperature.

Common Causes of Pontiac Tempest C251C OBD2 Code

A common cause of code C251C is the failure of Transmission Neutral Safety Switch Short Circuit To Battery, but there are several other possible causes as well, such as ;

Dirty Oil
1Camshaft Position Sensor circuit poor electrical connection
Damaged camshaft position (CMP) sensor
Open VPWR circuit

C251C is a kind of Chassis Trouble Code

Diagnosing chassis noises can be one of the most frustrating problems technicians face. Fortunately, manufacturers have engineered noise, vibration and harshness (NVH) diagnostic techniques and equipment to find the source of the noise.

Engine OBD 2 Codes website is a freeware resource center for engine trouble codes.

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C251C Pontiac Tempest OBD Code

C251C Pontiac Tempest Error Code Repair Process :

Common Causes of Pontiac Tempest C251C OBD2 Code

C251C code for other Pontiac cars