Diagnostic Trouble Code (DTC) Descriptions

1 Diagnostic Trouble code (DTC) Descriptions 1999 PCED OBDII SECTION 4: Diagnostic Subroutines Diagnostic Trouble code (DTC) Descriptions DTC Description Possible Causes Diagnostic Aides P0102 - Mass Air Flow (MAF) Circuit Low Input The MAF sensor circuit is monitored by the PCM for low air flow (or voltage) input through the comprehensive component monitor (CCM). If during key ON engine running the air flow (or voltage) changes below a minimum calibrated limit, the test fails. l MAF sensor disconnected l MAF circuit open to PCM l VPWR open to MAF sensor l PWR GND open to MAF sensor l MAF RTN circuit open to PCM l MAF circuit shorted to GND l Intake air leak (near MAF sensor ) l A closed [throttle indication throttle position (TP) sensor system] l Damaged MAF sensor l Damaged PCM A MAF V PID (MAF PID) reading less than volts (Refer to equivalent grams/second chart in Pinpoint Test DC) in continuous memory or key ON and engine running indicates a hard fault.

2 P0103 - Mass Air Flow (MAF) Circuit High Input The MAF sensor circuit is monitored by the PCM for high air flow (or voltage) input through the comprehensive component monitor (CCM). If during key ON engine OFF or key ON engine running the air flow (or voltage) changes above a maximum calibrated limit, the test fails. l MAF sensor screen is blocked l MAF circuit shorted to VPWR l Damaged MAF sensor l Damaged PCM A MAF V PID (MAF PID) reading less than volts (Refer to equivalent grams/second chart in Pinpoint Test DC) in continuous memory or key ON and engine running indicates a hard fault. P0106 - Barometric (BARO) Pressure sensor Circuit Performance Baro sensor input to the PCM is monitored and is not within the calibrated value.

3 L Slow responding BARO sensor l Electrical circuit failure l Damaged BARO sensor l Damaged PCM n VREF voltage should be between and volts n PID reading is in frequency ' (1 of 55) [3/23/2003 2:20:27 AM] Diagnostic Trouble code (DTC) Descriptions P0107 - BARO sensor Low Voltage Detected sensor operating voltage is less than volts (VREF), as a result it failed below the minimum allowable calibrated parameter. l Open in the circuit, or short to ground l VREF circuit open, or short to ground l Damaged BARO sensor l Damaged PCM n VREF should be greater than volts n PID reading is in frequency P0108 - BARO sensor High Voltage Detected sensor operating voltage is greater than volts (VREF), as a result it failed above maximum allowable calibrated parameter.

4 L VREF shorted to VWPR l BARO signal shorted to VPWR l Damaged BARO sensor l Damaged PCM n VREF should be less than volts. l PID reading is in frequency P0109 - BARO sensor Circuit Intermittent The sensor signal to the PCM is failing intermittently. l Loose electrical connection l Damaged BARO sensor Check harness and connection. P0112 - Intake Air Temperature (IAT) Circuit Low Input Indicates the sensor signal is less than Self-Test minimum. The IAT sensor minimum is volts or 121 C (250 F). l Grounded circuit in harness l Damaged sensor l Improper harness connection l Damaged PCM n Using signal simulation, disconnect sensor and simulate on sensor signal circuit.

5 Simulated signal and scan PID voltage value should be similar. If voltage is similar check sensor , if voltage is not similar check related circuit and PCM. P0113 - Intake Air Temperature (IAT) Circuit High Input Indicates the sensor signal is greater than Self-Test maximum. The IAT sensor maximum is volts or -50 C (-46 F). l Open circuit in harness l sensor signal short to power l Damaged sensor l Improper harness connection l Damaged PCM n Using signal simulation, disconnect sensor and simulate on sensor signal circuit. Simulated signal and scan PID voltage value should be similar.

6 If voltage is similar check sensor , if voltage is not similar check related circuit and PCM. P0117 - Engine Coolant Temperature (ECT) Circuit Low Input Indicates the sensor signal is less than Self-Test minimum. The ECT sensor minimum is volts or 121 C (250 F). Note on some vehicles that are not equipped with an ECT sensor , CHT can be used and can set this DTC. l Grounded circuit in harness l Damaged sensor l Improper harness connection l Damaged PCM n Using signal simulation, disconnect sensor and simulate on sensor signal circuit. Simulated signal and scan PID voltage value should be similar.

7 If voltage is similar check sensor , if voltage is not similar check related circuit and PCM. ' (2 of 55) [3/23/2003 2:20:27 AM] Diagnostic Trouble code (DTC) Descriptions P0118 - Engine Coolant Temperature (ECT) Circuit High Input Indicates the sensor signal is greater than Self-Test maximum. The ECT sensor maximum is volts or -50 C (-46 F). Note on some vehicles that are not equipped with an ECT sensor , CHT can be used and can set this DTC. l Open circuit in harness l sensor signal short to power l Damaged PCM l Improper harness connection l Damaged sensor n Using signal simulation, disconnect sensor and simulate on sensor signal circuit.

8 Simulated signal and scan PID voltage value should be similar. If voltage is similar check sensor , if voltage is not similar check related circuit and PCM. P0121 - Throttle position (TP) Circuit Performance Problem The TP sensor circuit is monitored by the PCM for a none closed throttle position at idle. If key ON engine running self-test terminates upon placing the transmission range selector in gear (DRIVE or REVERSE) or when closing the throttle (idle) after opening it (in PARK or NEUTRAL) the TP closed throttle position is not attained, the test fails. l Binding throttle linkage l Damaged throttle body l TP circuit open to PCM l Damaged TP sensor l SIG RTN circuit open to TP sensor Drive vehicle, bring to a stop, turn key OFF.

9 Start vehicle, run key ON engine running self-test at idle. Access KOER Diagnostic Trouble codes on scan tool. P0122 - Throttle position (TP) Circuit Low Input The TP sensor circuit is monitored by the PCM for a low TP rotation angle (or voltage) input through the comprehensive component monitor (CCM). If during key ON engine OFF or key ON engine running the TP rotation angle (or voltage) changes below a minimum calibrated limit, the test fails. l TP sensor not seated properly l TP circuit open to PCM l VREF open to TP sensor l TP circuit short to GND l Damaged TP sensor l Damaged PCM A TP PID (TP V PID) reading less than ( volt) in key ON engine OFF, continuous memory or key ON engine running indicates a hard fault.

10 ' (3 of 55) [3/23/2003 2:20:27 AM] Diagnostic Trouble code (DTC) Descriptions P0123 - Throttle position (TP) Circuit High Input The TP sensor circuit is monitored by the PCM for a high TP rotation angle (or voltage) input through the comprehensive component monitor (CCM). If during key ON engine OFF or key ON engine running the TP rotation angle (or voltage) changes above maximum calibrated limit, the test fails. l TP sensor not seated properly l TP circuit short to PWR l VREF short to PWR l SIG RTN circuit open to TP sensor l Damaged TP sensor l Damaged PCM A TP PID (TP V PID) reading greater than 93% ( volts) in key ON engine OFF, continuous memory or key ON engine running indicates a hard fault.