B1503

DTC B1503-H/L: Evaporator Temperature Sensor and/or Its Circuit Malfunction

Wiring Diagram










DTC Detecting Condition and Trouble Area






DTC Confirmation Procedure

1) Connect scan tool to DLC with ignition switch turned OFF.
2) Turn ON ignition switch and clear DTC using scan tool.
3) Check DTC.

DTC Troubleshooting

NOTE:

When DTC B1502, B1511, B1512 and B1530 are indicated together, it is possible that "BLK/RED" wire circuit open.

1. Evaporator temperature sensor signal circuit check

Disconnect evaporator temperature sensor connector with ignition switch turned OFF.
Check for proper connection to evaporator temperature sensor at "WHT/BLK" and "BLK/RED" wire terminals.
If OK, measure voltage between "WHT/BLK" wire terminal of evaporator temperature sensor connector and vehicle body ground with ignition switch turned ON.

Is voltage 4 - 6 V?
YES -
Go to Step 5.
NO -
Go to Step 2.

2. Evaporator temperature sensor signal circuit check

Disconnect connector from HVAC control module with ignition switch turned OFF.
Check for proper connection to HVAC control module connector at "G52-20" and "G52-26" terminals.
If OK, measure resistance between "WHT/BLK" wire terminal of evaporator temperature sensor connector and "G52-20" terminal of HVAC control module connector.

Is resistance below 5 ohms?
YES -
Go to Step 3.
NO -
"WHT/BLK" wire open or high resistance circuit.

3. Evaporator temperature sensor signal circuit check

Measure resistance between "WHT/BLK" wire terminal of evaporator temperature sensor connector and vehicle body ground.

Is resistance infinity?
YES -
Go to Step 4.
NO -
"WHT/BLK" wire shorted to ground circuit.

4. Evaporator temperature sensor signal circuit check

Measure voltage between "WHT/BLK" wire terminal of evaporator temperature sensor connector and vehicle body ground with ignition switch turned ON.

Is voltage 0 V?
YES -
Go to Step 5.
NO -
"WHT/BLK" wire shorted to other circuit.

5. Evaporator temperature sensor ground circuit check

Connect HVAC control module connector with ignition switch turned OFF.
Measure resistance between "BLK/RED" wire terminal of evaporator temperature sensor connector and vehicle body ground.

Is resistance below 5 ohms?
YES -
Go to Step 7.
NO -
Go to Step 6.

6. Evaporator temperature sensor ground circuit check

Measure resistance between "G52-26" terminal of HVAC control module connector and vehicle body ground.

Is resistance below 5 ohms?
YES -
"BLK/RED" wire open or high resistance circuit.
NO -
HVAC control module faulty.

7. Evaporator temperature sensor check

Check evaporator temperature sensor referring to A/C Evaporator Temperature Sensor Inspection A/C Evaporator Temperature Sensor Inspection.

Is it in good condition?
YES -
HVAC control module faulty.
NO -
Evaporator temperature sensor faulty.