Diagnostic Test

WARNING: This page is about a different car, the 2006 Dodge Magnum, 2006 Dodge Charger, and 2006 Chrysler 300. However, it is still accessible from the selected car via links, so may be relevant.

1) CHECK (C21) EVAPORATOR TEMPERATURE SENSOR SIGNAL CIRCUIT FOR A SHORT TO VOLTAGE

Fig 1: Checking Evaporator Temperature Sensor Signal Circuit For Short To Voltage
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Disconnect the A/C Heater Control C2 harness connector.

Turn the ignition on.

Measure the voltage of the (C21) Evaporator Temperature Sensor Signal circuit.

Is the voltage above 0.2 volts?

Yes
1. Repair the (C21) Evaporator Temperature Sensor Signal circuit for a short to voltage.
2. Perform BODY VERIFICATION TEST - VER 1. (Refer to ELECTRICAL/ELECTRONIC CONTROL MODULES/FRONT CONTROL MODULE - DIAGNOSIS AND TESTING) .
No
1. Go To step 2).
2) CHECK (C21) EVAPORATOR TEMPERATURE SENSOR SIGNAL CIRCUIT, (C121) SENSOR GROUND CIRCUIT, & EVAPORATOR TEMPERATURE SENSOR

Fig 2: Measuring Resistance Between Evaporator Temperature Sensor Signal & Ground Circuits
Courtesy of DAIMLERCHRYSLER CORP.

Turn the ignition off.

Measure the resistance between the (C21) Evaporator Temperature Sensor Signal circuit and the (C121) Sensor Ground circuit in the A/C Heater Control C2 harness connector. The approximate circuit resistance should be as follows:
- 1468 ohms @ 40°C (104°F)
- 1800 ohms @ 35°C (95°F)
- 2221 ohms @ 30°C (86°F)
- 2757 ohms @ 25°C (77°F)
- 3443 ohms @ 20°C (68°F)
- 4330 ohms @ 15°C (59°F)
- 5485 ohms @ 10°C (50°F)
- 6998 ohms @ 5°C (41°F)
- 7354 ohms @ 4°C (39°F)
- 7731 ohms @ 3°C (37°F)
- 8130 ohms @ 2°C (36°F)
- 8553 ohms @ 1°C (34°F)
- 9000 ohms @ 0°C (32°F)
Is the resistance within the specifications?

Yes
1. Replace the A/C Heater Control in accordance with the Service Information.
2. Perform BODY VERIFICATION TEST - VER 1. (Refer to ELECTRICAL/ELECTRONIC CONTROL MODULES/FRONT CONTROL MODULE - DIAGNOSIS AND TESTING) .
No
1. Go To step 3).
3) CHECK (C21) EVAPORATOR TEMPERATURE SENSOR SIGNAL CIRCUIT FOR AN OPEN

Fig 3: Checking Evaporator Temperature Sensor Signal Circuit For Open
Courtesy of DAIMLERCHRYSLER CORP.

Disconnect the Evaporator Temperature Sensor harness connector.

Measure the resistance of the (C21) Evaporator Temperature Sensor Signal circuit between the Evaporator Temperature Sensor harness connector and the A/C Heater Control C2 harness connector.

Is the resistance below 5.0 ohms?

Yes
1. Go To step 4).
No
1. Repair the (C21) Evaporator Temperature Sensor Signal circuit for an open.
2. Perform BODY VERIFICATION TEST - VER 1. (Refer to ELECTRICAL/ELECTRONIC CONTROL MODULES/FRONT CONTROL MODULE - DIAGNOSIS AND TESTING) .
4) CHECK (C121) SENSOR GROUND CIRCUIT FOR AN OPEN

Fig 4: Checking Sensor Ground Circuit For Open
Courtesy of DAIMLERCHRYSLER CORP.

Measure the resistance of the (C121) Sensor Ground circuit between the Evaporator Temperature Sensor harness connector and the A/C Heater Control C2 harness connector.

Is the resistance below 5.0 ohms?

Yes
1. Replace the Evaporator Temperature Sensor in accordance with the Service Information.
2. Perform BODY VERIFICATION TEST - VER 1. (Refer to ELECTRICAL/ELECTRONIC CONTROL MODULES/FRONT CONTROL MODULE - DIAGNOSIS AND TESTING) .
No
1. Repair the (C121) Sensor Ground circuit for an open.
2. Perform BODY VERIFICATION TEST - VER 1. (Refer to ELECTRICAL/ELECTRONIC CONTROL MODULES/FRONT CONTROL MODULE - DIAGNOSIS AND TESTING) .