DTC Check (Sensor Check)
After indicator check is completed, system enters DTC check mode automatically. Stored diagnostic trouble codes will appear as blinks of A/C indicator. See DIAGNOSTIC TROUBLE CODE IDENTIFICATION table. Turn blower switch from AUTO position to exit self-diagnostics.
| DTC Number | Condition/Affected Circuit |
|---|
| 11 (1) | Room Temperature Sensor Circuit |
| 12 (2) | Ambient Temperature Sensor Circuit |
| 13 | Evaporator Temperature Sensor Circuit |
| 14 | Engine Coolant Temperature Sensor Circuit |
| 21 (3) | Solar Sensor Circuit |
| 22 (4) | Compressor Lock Sensor Circuit |
| 23 | Pressure Switch Circuit |
| 31 & 41 | Air Mix Damper Position Sensor Circuit |
| 32 & 42 | Air Inlet Damper Position Sensor Circuit |
| 33 & 43 | Air Outlet Damper Position Sensor Circuit |
| (1) If in-vehicle temperature is -4°F (-20°C) or less, Code 11 may set even though system is normal. (2) If ambient air temperature is -50°F (-58°C) or less, DTC 12 may set even though system is normal. (3) If testing is done in a dark area, DTC 21 may set even though system is normal. Shine a light at solar sensor and recheck codes. (4) Compressor lock is indicated only for a current malfunction. |
| (1) | If in-vehicle temperature is -4°F (-20°C) or less, Code 11 may set even though system is normal. |
| (2) | If ambient air temperature is -50°F (-58°C) or less, DTC 12 may set even though system is normal. |
| (3) | If testing is done in a dark area, DTC 21 may set even though system is normal. Shine a light at solar sensor and recheck codes. |
| (4) | Compressor lock is indicated only for a current malfunction. |
DIAGNOSTIC TROUBLE CODE IDENTIFICATION
CLEARING DIAGNOSTIC TROUBLE CODES
Remove HTR (30-amp) fuse from engine room junction block for at least 10 seconds.
DTC 12: AMBIENT TEMPERATURE SENSOR CIRCUIT
- Remove ECM, leaving harness connectors connected. Turn ignition on. Backprobe between ECM connector terminals No. 18 (Brown wire) and No. 23 (White/Green wire). At 77°F (25°C), about 1.35-1.75 volts should be present. At 104°F (40°C), about .85-1.25 volts should be present. If voltages are to specification, ambient temperature sensor is okay. If voltages are not to specification, go to next step.
- Turn ignition off. Disconnect ambient temperature sensor connector. Measure resistance between sensor terminals. See «AMBIENT TEMPERATURE SENSOR»(ref-98934-S19378942472001072000000) under COMPONENT TESTS. If resistances are not to specification, replace ambient temperature sensor. If resistances are to specification, check multiplex control system. See appropriate MULTIPLEX CONTROL SYSTEMS article in ACCESSORIES & EQUIPMENT.
DTC 13: EVAPORATOR TEMPERATURE SENSOR CIRCUIT
- Remove A/C control assembly, leaving harness connectors connected. See «A/C CONTROL ASSEMBLY»(ref-98934-S41360912392001072500000) under REMOVAL & INSTALLATION. Turn ignition on. Backprobe between connector A9 terminals No. 1 (White wire) and No. 2 (White wire) at A/C control assembly harness connector. see scheme 4 At 32°F (0°C), about 2.0-2.4 volts should be present. At 59°F (15°C), about 1.4-1.8 volts should be present. If voltages are to specification, evaporator temperature sensor circuit is okay. If voltages are not to specification, go to next step.
- Turn ignition off. Disconnect evaporator temperature sensor connector. Measure resistance between sensor terminals. See «EVAPORATOR TEMPERATURE SENSOR»(ref-98934-S01209747422001072000000) under COMPONENT TESTS. If resistances are not to specification, replace evaporator temperature sensor. If resistances are to specification, check wiring between A/C control assembly and evaporator temperature sensor. Repair wiring as necessary. See «WIRING DIAGRAMS»(ref-98934-S03455350802001070200000). If wiring is okay, replace A/C control assembly.
DTC 14: ENGINE COOLANT TEMPERATURE SENSOR
- Connect scan tool to Data Link Connector 3 (DLC3). Check coolant temperature sensor using scan tool's DATA LIST menu. If coolant temperature sensor is okay, replace A/C control assembly. If coolant temperature sensor is not okay, go to next step.
- Turn ignition off. Disconnect coolant temperature sensor connector. Measure resistance between sensor terminals. See «COOLANT TEMPERATURE SENSOR RESISTANCE SPECIFICATIONS»(ref-98934-S25367606272001072500000) table. If resistances are not to specification, replace coolant temperature sensor. If resistances are to specification, check wiring between ECM and coolant temperature sensor. Repair wiring as necessary. See «WIRING DIAGRAMS»(ref-98934-S03455350802001070200000) . If wiring is okay, check multiplex control system. See appropriate MULTIPLEX CONTROL SYSTEMS article in ACCESSORIES & EQUIPMENT.
| Sensor Temperature - °F (°C) | (1) Ohms |
|---|
| 68 (20) | 2000-3000 |
| 176 (80) | 200-400 |
| (1) As temperature increases, resistance should gradually decrease. |
| (1) | As temperature increases, resistance should gradually decrease. |
COOLANT TEMPERATURE SENSOR RESISTANCE SPECIFICATIONS
DTC 21: SOLAR SENSOR CIRCUIT
- Remove A/C control assembly, leaving harness connectors connected. See «A/C CONTROL ASSEMBLY»(ref-98934-S41360912392001072500000) under REMOVAL & INSTALLATION. Turn ignition on. Backprobe between connector A9 terminals No. 5 (White wire) and No. 6 (White wire) at A/C control assembly harness connector. see scheme 4 With light on sensor, less than 4 volts should be present. With sensor covered, about 4-4.5 volts should be present. If voltages are to specification, sensor is okay. If voltages are not to specification, go to next step.
- Turn ignition off. Remove solar sensor. Measure resistance between sensor terminals. See «SOLAR SENSOR»(ref-98934-S03842253132001072000000) under COMPONENT TESTS. If resistances are not to specification, replace solar sensor. If resistances are to specification, check wiring between A/C control assembly and solar sensor. Repair wiring as necessary. See «WIRING DIAGRAMS»(ref-98934-S03455350802001070200000). If wiring is okay, replace A/C control assembly.
DTC 22: COMPRESSOR LOCK SENSOR CIRCUIT
- Check compressor drive belt tension. See «SPECIFICATIONS»(ref-98934-S13455747942001072700000) table. Adjust drive belt tension as necessary. If drive belt tension is okay, go to next step.
- Disconnect compressor lock sensor 4-pin connector. Measure resistance between connector terminals No. 2 (Brown/White wire) and No. 4 (White/Blue wire). (Scheme 4) If resistance is not 65-125 ohms at 68°F (20°C), replace compressor. If resistance is 65-125 ohms at 68°F (20°C), check wiring between A/C control assembly and compressor lock sensor. Repair wiring as necessary. See «WIRING DIAGRAMS»(ref-98934-S03455350802001070200000). If wiring is okay, compressor lock sensor circuit is okay.
Scheme 4
DTC 23: PRESSURE SWITCH CIRCUIT
- Remove A/C control assembly, leaving harness connectors connected. See «A/C CONTROL ASSEMBLY»(ref-98934-S41360912392001072500000) under REMOVAL & INSTALLATION. Install manifold gauge set. Turn ignition on. Backprobe voltmeter between connector A18 terminal No. 11 (Blue/Yellow wire) and ground. see scheme 4
- Start engine. Turn A/C on. Pressure switch operation should be as specified. (Scheme 5) If pressure switch operation is not as specified, go to next step. If pressure switch operation is as specified, circuit is okay.
- Disconnect pressure switch connector. Check for continuity between pressure switch terminals No. 1 and 4 at refrigerant pressures specified. (Scheme 5)and (Scheme 6). Replace pressure switch if operation is not as specified. If switch is okay, inspect wiring harness and connectors between switch and A/C control assembly. If wiring harness and connectors are okay, substitute a known-good A/C control assembly. Retest system.
Scheme 5
Scheme 6
DTC 31 & 41: AIR MIX DAMPER POSITION SENSOR CIRCUIT
- Remove A/C control assembly, leaving harness connectors connected. See «A/C CONTROL ASSEMBLY»(ref-98934-S41360912392001072500000) under REMOVAL & INSTALLATION. Turn ignition on. Change set temperature to activate air mix damper and measure voltage between connector A9 terminals No. 15 (White wire) and No. 16 (White wire). see scheme 4 At maximum cool position, about 3.5-4.5 volts should be present. At maximum warm position, about.5-1.5 volts should be present. If voltages are to specification, air mix damper position sensor circuit is okay. If voltages are not to specification, go to next step.
- Remove air mix servomotor. See «AIR MIX SERVOMOTOR»(ref-98934-S25085863652001072300000) under REMOVAL & INSTALLATION. Measure resistance between air mix servomotor connector terminals. See «AIR MIX SERVOMOTOR»(ref-98934-S07117887272001072000000) under COMPONENT TESTS. If resistances are not to specification, replace air mix control servomotor. If resistances are to specification, inspect wiring harness and connectors between servomotor and A/C control assembly. If wiring harness and connectors are okay, replace A/C control assembly. Retest system.
DTC 32 & 42: AIR INLET DAMPER POSITION SENSOR
- Remove A/C control assembly, leaving harness connectors connected. See «AIR MIX SERVOMOTOR»(ref-98934-S25085863652001072300000) under REMOVAL & INSTALLATION. Turn ignition on. Press fresh air/recirculated air buttons to change air inlet between fresh air and recirculated air modes. Measure voltage between connector A9 terminals No. 18 (White wire) and No. 19 (White wire) when air inlet servomotor operates. see scheme 4 When operated in recirculated air mode, about 3.5-4.5 volts should be present. When operated in fresh air mode, about.5-1.8 volts should be present. If voltages are to specification, air inlet damper position sensor is okay. If voltages are not to specification, go to next step.
- Test air inlet servomotor. See «AIR INLET SERVOMOTOR»(ref-98934-S30818313322001072000000) under COMPONENT TESTS. Replace servomotor if defective. If servomotor is okay, check wiring and connectors between A/C control assembly and air inlet control servomotor. See «WIRING DIAGRAMS»(ref-98934-S03455350802001070200000). Repair wiring as necessary. If wiring is okay, replace A/C control assembly.
DTC 33 & 43: AIR OUTLET DAMPER POSITION SENSOR
- Remove A/C control assembly, leaving harness connectors connected. See «A/C CONTROL ASSEMBLY»(ref-98934-S41360912392001072500000) under REMOVAL & INSTALLATION. Turn ignition on. Backprobe between connector A9 terminals No. 8 (White wire) and No. 9 (White wire) at A/C control assembly harness connector. see scheme 4 When operated in face (vent) mode, about 3.5-4.5 volts should be present. When operated in defrost mode, about.5-1.8 volts should be present. If voltages are to specification, air outlet damper position sensor is okay. If voltages are not to specification, go to next step.
- Test air outlet damper position sensor. See «AIR OUTLET SERVOMOTOR»(ref-98934-S15912832702001072000000) under COMPONENT TESTS. Replace sensor if defective. If sensor is okay, check wiring and connectors between A/C control assembly and air inlet control servomotor. See «WIRING DIAGRAMS»(ref-98934-S03455350802001070200000). Repair wiring as necessary. If wiring is okay, replace A/C control assembly.
