Ignore code 12. That just means the ignition switch was turned off.
Code 13 means there was "No change in the MAP sensor voltage from start to run". When you turn on the ignition switch, the sensor voltage represents barometric pressure. When the engine is running, it represents intake manifold vacuum. Lower vacuum equates to higher load on the engine which means it needs more fuel. The sensor could be failing, but more likely the vacuum hose is cracked or disconnected. A failed sensor will not prevent the engine from starting, but it can cause a running engine to stall. A trick we used to get the car into the shop was to simply keep the gas pedal in motion. As long as it was moving slowly up or down, the engine would run. When this code is set, the engine computer knows it can't rely on the reading so it injects an approximate value from memory. Also, the computer tests various sensors against each other under different conditions, so having a MAP sensor code in memory will prevent other codes from being set. Therefore, once the cause for this code is repaired, a new code could appear.
You must also be aware that you can't use the common MAP sensor with a turbocharged engine. Your intake manifold will go from a vacuum to pressure when the turbo kicks in, and the MAP sensor must be capable of reading pressure as well as vacuum.
Code 22 is for the coolant temperature sensor. This sensor will not affect engine operation significantly. It is common practice to unplug it to put the ignition system into base timing mode to adjust ignition timing. The radiator fan will turn on while the sensor is disconnected, and the "Check Engine" light will turn on. The light and fan will go off when the sensor is reconnected, but the fault code will remain in memory. It will erase automatically after about 50 engine starts.
Code 55 just means that's the end of the list of codes.
A real common cause of failure to start in a 4 cylinder engine is a defective Hall Efect Switch. That's the pickup assembly under the rotor in the distributor.
Tuesday, January 26th, 2010 AT 2:41 AM