MTC

B1032-EVAPORATOR FIN TEMPERATURE SENSOR CIRCUIT HIGH (MTC)

For the Manual Temperature Control (MTC) circuit diagram Refer to HEATING & AIR CONDITIONING - SCHEMATICS AND DIAGRAMS.

For a complete wiring diagram refer to Wiring Section.

B1032-Evaporator Fin Temperature Sensor Circuit High (MTC):

WHEN MONITORED
With the ignition on.

SET CONDITION
If the Evaporator Temperature Sensor input is out of range toward the high voltage threshold, (A/D counts reach high threshold of 240). This DTC has a maturing time of 5 seconds and a de-maturing time of 10 seconds. If the DTC's status changes from active to stored it will stay in memory for 100 ignition cycles.

POSSIBLE CAUSES
- (C21) Evaporator temperature sensor signal circuit shorted to voltage
- (C21) Evaporator temperature sensor signal circuit open
- (C121) Sensor ground circuit open
- Evaporator temperature sensor
- A/C heater control

NOTE: This DTC must be active for the results of this test to be valid. Do not perform this test if this DTC is stored. Refer to HVAC System Test (MTC) for stored DTC test procedures.

Diagnostic Test

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




Turn the ignition off.
Disconnect the A/C Heater Control C1 harness connector.
Turn the ignition on.
Measure the voltage of the (C21) Evaporator Temperature Sensor Signal circuit.

Q: Is the voltage above 0.2 volt?

YES: Repair the (C21) Evaporator Temperature Sensor Signal circuit for a short to voltage. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Go To 2

2. CHECK (C21) EVAPORATOR TEMPERATURE SENSOR SIGNAL CIRCUIT, (C121) SENSOR GROUND CIRCUIT, & EVAPORATOR TEMPERATURE SENSOR




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 C1 harness connector. The approximate circuit resistance should be as follows:
- 2925 ohms @ 38° C (100° F)
- 4050 ohms @ 30° C (86° F)
- 4985 ohms @ 25° C (77° F)
- 6498 ohms @ 19° C (66° F)
- 8989 ohms @ 12° C (54° F)
- 13307 ohms @ 4° C (39° F)
- 14860 ohms @ 2° C (36° F)

Q: Is the resistance within the specifications?

YES: Replace the A/C Heater Control in accordance with the Service Information. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Go To 3

3. CHECK (C21) EVAPORATOR TEMPERATURE SENSOR SIGNAL CIRCUIT FOR AN OPEN




Disconnect the in-line C202 harness connector.
Measure the resistance of the (C21) Evaporator Temperature Sensor Signal circuit between the A/C Heater Control C1 harness connector and the in-line C202 (IP SIDE) harness connector.

Q: Is the resistance below 5.0 ohms?

YES: Go To 4
NO: Repair the (C21) Evaporator Temperature Sensor Signal circuit for an open between the A/C Heater Control C1 harness connector and the in-line C202 (IP SIDE) harness connector. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

4. CHECK (C121) SENSOR GROUND CIRCUIT FOR AN OPEN




Measure the resistance of the (C121) Sensor Ground circuit between the A/C Heater Control C1 harness connector and the in-line C202 (IP SIDE) harness connector.

Q: Is the resistance below 5.0 ohms?

YES: Go To 5
NO: Repair the (C121) Sensor Ground circuit for an open between the A/C Heater Control C1 harness connector and the in-line C202 (IP SIDE) harness connector. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

5. CHECK (C21) EVAPORATOR TEMPERATURE SENSOR SIGNAL CIRCUIT FOR AN OPEN




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 in-line C202 (HVAC SIDE) harness connector.

Q: Is the resistance below 5.0 ohms?

YES: Go To 6

NO: Repair the (C21) Evaporator Temperature Sensor Signal circuit for an open between the Evaporator Temperature Sensor harness connector and the in-line C202 (HVAC SIDE) harness connector. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

6. CHECK (C121) SENSOR GROUND CIRCUIT FOR AN OPEN




Measure the resistance of the (C121) Sensor Ground circuit between the Evaporator Temperature Sensor harness connector and the in-line C202 (HVAC SIDE) harness connector.

Q: Is the resistance below 5.0 ohms?

YES: Replace the Evaporator Temperature Sensor in accordance with the Service Information. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Repair the (C121) Sensor Ground circuit for an open between the Evaporator Temperature Sensor harness connector and the in-line C202 (HVAC SIDE) harness connector. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test