Probable Cause

DTC PROBABLE CAUSE

DTC 13 - Indicates that the oxygen sensor circuit or sensor was open for one minute while off idle.
DTC 14 - Sets if the sensor or signal line becomes grounded for 3 seconds.
DTC 15 - Sets if the sensor, connections, or wires open for 3 seconds.
DTC 21 - TP voltage greater than 2.5 volts for 3 seconds with less than 1200 rpm.
DTC 22 - A short to ground or open signal circuit will set DTC in 3 seconds.
DTC 24 - No vehicle speed present during a road load decel.
DTC 32 - Vacuum switch shorted to ground on start up OR Switch not closed after the ECM has commanded EGR for a specified period of time OR EGR solenoid circuit open for a specified period of time.
DTC 33 - MAP sensor output high for 5 seconds or an open signal circuit.
DTC 34 - Low or no output from sensor with engine running.
DTC 42 - ECM has seen an open or grounded IC or bypass circuit.
DTC 43 - Signal to the ECM has remained low for too long or the system has failed a functional check.
DTC 44 - Sets if oxygen sensor voltage remains below .2 volt for about 20 seconds.
DTC 45 - Sets if oxygen sensor voltage remains below .7 volt for about 1 minute.
DTC 51 - Faulty PROM or ECM.
DTC 53 - System overvoltage. Indicates a basic generator problem.
DTC 54 - Sets when the fuel pump voltage is less than 2 volts when reference pulses are being received.
DTC 55 - Faulty ECM.