DTC 02

1 Of 2:

2 Of 2:

Circuit Description:

The feedback Potentiometer (POT) sensor measures the position of the temperature door The heater and A/C programmer uses this information to drive the temperature door motor. A low feedback voltage represents a hot temperature door position and high feedback voltage represents a cold temperature door position. If Codes 01 and 02 have been set, the programmer will enter a default value of 128 counts (mid position) so driver may still control full hot and full cold.

NOTICE: Do not attempt to cycle the mix door motor removed from the heater case as permanent damage to the motor will result.

Important
^ The A/C programmer logic will be lost if the courtesy and radio fuses or the negative battery cable are removed with the ignition in the "ON" position. The programmer logic will be restored by removing the negative battery cable and reinstalling after 1 minute.

Test Description:

Number(s) below refer to circled number(s) on the diagnostic chart.

Codes 01-02 indicate the programmer has seen a fault at "D13".
OR
Mix motor/door will not go to the hot or cold position when programmer commands it, causing the programmer to see low or high voltage feedback from the POT.

1. This test eliminates the possibility of a false code being set. With the ignition "OFF," removing the negative battery cable and installing after 1 minute will clear the programmer memory.
2. This test will determine if the HVAC programmer is commanding the temperature door motor to travel its entire range. If parameter 34 is not within the specified range, full hot and full cold, the programmer should be replaced.
3. This test visually confirms that the temperature door is actually moving.
4. This test is to determine if the temperature door motor potentiometer is within the specified resistance range for full hot and full cold door position. If temperature door motor is not within the specified range, Step 6 should be performed before replacing the motor.
5. This test will determine if the temperature motor is receiving operating voltage from the programmer. If approximately 8 volts are present at C295, the temperature door motor is suspect.
6. This test will determine if the temperature door is misaligned causing the temperature door motor potentiometer resistance to be outside the specified range.
7. This test will determine if there is output voltage at the programmer to activate the temperature door motor. If voltage is present at the programmer and not at C295, an open exists in the circuit. If no voltage is present at the programmer, it should be replaced.

Diagnostic Aids:

^ If Code 01 or 02 are intermittent, check connectors and wire harness for possible open or short.
^ If the temperature door has more than 5 mm of free play, replace the heater case assembly.