Codes Circuit or System Probable cause
13 Oxygen sensor circuit Check the wiring & connectors from the O2 sensors
14 Coolant sensor circuit (High temp indicated)If the engine is experiencing overheating problems, the problem must be rectified before continuing. Check all wiring & connectors associated with the sensor. Replace the coolant sensor
15 Coolant sensor circuit (Low temp indicated)
See above. Also check the thermostat for proper operation.
16 Low resolution pulse Ignition is not detecting the low resolution (4 pulses per crankshaft revolution)
21 TPS circuit (signal voltage high) Check for sticking or misadjusted TPS. Check all wiring & connecting at the TPS & at the ECM/PCM. Adjust or replace TPS.
22 TPS circuit (signal voltage low) See Above.
23 IAT sensor Low temp indicated.
24 VSS A faulty in this circuit should be indicated only while the vehicle is in motion. Disregard code 24 if set when drive wheels are not turning. Check connections at the ECM/PCM. Check the TPS setting.
25 IAT sensor Check the resistance of the IAT sensor. Check the wiring & connection to the sensor. Replace the IAT sensor.
26 Evaporative purge control solenoid circuit EVAP purge control solenoid circuit is faulty. Check the wiring harness.
27 EGR vacuum control solenoid circuit Check the EGR vaccum soleoid circuit.
28 Transmission range Check the transmission range control circuit.
29 Secondary air injection Check the 2nd air injection system for an open circuit in the wiring.
32 EGR failure Check the vacuum source & all vacuum lines. Check the system electrical connectors at the ECM/PCM. Replace EGR valve or ECM/PCM as necessary.
33 MAP signal voltage high Check vacuum hoses from MAP sensor. Check electrical sensor or circuit connections at the ECM/PCM. Replace MAP sensor