DTC 1-2-4 and 1-2-6

DTCs 1-2-4 AND 1-2-6. PASSENGER COMPARTMENT TEMPERATURE SENSOR OPEN CIRCUIT OR SHORT TO 12 V:





DTC 1-2-4: Driver side passenger compartment temperature sensor open circuit or shorted to 12 V.
DTC 1-2-6: Passenger side passenger compartment temperature sensor open circuit or shorted to 12 V.

- Condition for DTC:
If signal from passenger compartment temperature sensor is missing or shorted to 12 V, the control module records the fault and stores the DTC.

- Cause of fault:
Open circuit in passenger compartment temperature sensor or wire, or short in wire to 12 V.

- Symptoms:
Fault warning to driver. LEDs by A/C and REC buttons flash for 20 sec.
The control module substitutes the faulty signal with an estimated value based on the desired temperatures from both temperature switches and the sensor signal from the side which is working. If the sensor signal is faulty on both the drivers and passenger side, the control module uses the temperature value from that side temperature switch only.

Check Other DTCs:





1-2-2, 1-2-4, 1-2-6, 2-1-1, 2-2-1, 2-3-1, 2-3-3 and 2-3-5. Are these DTCs stored at the same time?
If YES, this means there is an open circuit in a common ground (GND) wire.
- Ignition off.
- Check wire between branching point 23/306 and connector A pins A:9 and A:10 to control module for open circuit. Checking Wires
Rectify open circuit.
Check DTC. Test Procedures
If NO, this means there is an open circuit or short in a wire which runs only between the control module and the passenger compartment temperature sensor to which the DTC refers. Go to the next step "Connect Test Unit To Control Module".

Connect Test Unit To Control Module:





- Ignition off.
- Connect test unit between control unit and A/C system and check GND points. Connecting and Disconnecting Test Unit
- Go to the next step "Check Voltage To Passenger Compartment Temperature Sensor".

Check Voltage To Passenger Compartment Temperature Sensor:











- Ignition on.
- Connect a voltmeter:
On driver side, across # 10 (0 V) and # 12.
On passenger side, across # 10 (0 V) and # 13.
At 20 °C, voltmeter should read approx. 2.6 V (voltage varies with passenger compartment temperature).
- If voltmeter reads 5 V, open circuit in wire or passenger compartment temperature sensor. Go to the step "Check Wire Resistance".
- If voltmeter reads 12 V, short in wire between connector pin 5 and connector A to control module:
On driver's side, to connection A:12.
On passenger side, to connection A:13.
Check wire for short to 12 V. Checking Wires
Rectify short.
Check DTC. Test Procedures

Check Wire Resistance:











- Ignition off.
- Disconnect adapter from control module.
- Disconnect connector from passenger compartment temperature sensor. Service and Repair
- Bridge over pins 2 and 5 of wire connector.
- Connect an ohmmeter:
On driver's side, across # 10 and # 12.
On passenger side, across # 10 and # 13.
- If ohmmeter reads 0 ohm, wire is OK. Open circuit in passenger compartment temperature sensor. Go to the next step "Check Passenger Compartment Temperature Sensor".
- If ohmmeter reading Is infinite, passenger compartment temperature sensor is OK. Open circuit in wire.
Check GND wire between connector pin 3 and connector A pin A:10 to control module for open circuit. Checking Wires
Check live wire between connector pin 5 and connector A to control module for open circuit:
On driver's side, to pin A:12.
On passenger side, to pin A:13. Checking Wires
Rectify open circuit.
Check DTC. Test Procedures

Check Passenger Compartment Temperature Sensor:








- Ignition off.
- Disconnect connector from passenger compartment temperature sensor. Service and Repair
- Connect an ohmmeter across passenger compartment temperature sensor pins 3 and 5.
- If value is OK, ohmmeter should read approx. 8-12 K ohms.
- If value is not OK, ohmmeter reading is infinite, there is an open circuit in the passenger compartment temperature sensor. Replace passenger compartment temperature sensor and refit in reverse order.
Check DTC. Test Procedures