My 99 Jeep Wrangler failed inspection for a P0650 mil malfunction. Is this a wiring problem or a bad bulb/fuse?
DTC P0650 represents an issue with the actual check engine light (malfunction indicator lamp). Ignition voltage is supplied directly to the malfunction indicator lamp (MIL). The powertrain control module (PCM) controls the lamp by grounding the control circuit via an internal switch called a driver. The primary function of the driver is to supply the ground for the component being controlled. The driver has a fault line which is monitored by the PCM. When the PCM is commanding a component ON, the voltage of the control circuit should be low, near 0 volts. When the PCM is commanding the component control circuit OFF, the voltage potential of the circuit should be high, near battery voltage. If the fault detection circuit senses a voltage other than what is expected, the fault line status will change causing the diagnostic trouble code (DTC) to set.
A DTC P0650 indicates a problem with the circuit to the actual check engine light itself. If the fault is current, check if the check engine (service engine soon) lamp comes on when you turn the ignition on, If not, we will need to pull the engine control computer and ground the wire that goes to the light. If the light comes on, it is a failed pcm which must be replaced and reprogrammed. If not, it is either the circuit to the cluster or the cluster itself.
Mar 26, 2011 |
Jeep Wrangler Cars & Trucks