Q: COLD ENGINE BLOWER CONTROL DIAGNOSIS-NO ERROR CODES

PINPOINT TEST Q: COLD ENGINE BLOWER CONTROL DIAGNOSIS-NO DIAGNOSTIC ERROR CODE

Q1 CHECK COLD ENGINE BLOWER MOTOR OPERATION

- With engine coolant below 49°C (120°F) (cold engine) and control set at 32°C (90°F) AUTOMATIC, check for heater blower motor operation.Blower motor should operate at low blower for 3 1/2 minutes or until engine coolant temperature reaches 49°C (120°F), whichever occurs first.

- Does blower motor operate at low speed with engine coolant temperature below 49°C (120°F) and before 3 1/2 minutes have elapsed since engine start-up?

- Yes
Go to Q2.

- No
Go to Q4.

Q2 CHECK WARM ENGINE BLOWER MOTOR OPERATION

- Allow engine to operate until blower motor speed increases from low blower. Check amount of time required for blower motor speed to increase.

- Does blower motor speed increase before 3 1/2 minutes have elapsed?

- Yes
Cold engine lock out functioning properly. Perform Pinpoint Test Step A1.

- No
Go to Q3.

Q3 PERFORM EATC SELF DIAGNOSTICS

- Press OFF and FLOOR buttons simultaneously and then press AUTOMATIC button within two seconds. Self test may run as long as 30 seconds. After self test, error codes will be displayed. Record all error codes and press the blue (Cooler) button.

- Was error code 115 displayed?

- Yes
Go to Q5.

- No
Go to Q4.

Q4 CHECK BLOWER MOTOR OPERATION

- Select NORM A/C, turn ignition key to RUN and rotate blower thumbwheel to HI.

- Does blower motor operate?

Yes
Replace EATC control assembly. Restore vehicle. Retest system.

- No
Refer to General System Diagnosis to diagnose blower motor.

Q5 CHECK ENGINE COOLANT LEVEL

- Check engine coolant level.

- Is engine coolant level low?

- Yes
Add recommended coolant mixture to bring coolant to specified level. Retest system for proper operation.

- No
Go to Q6.

Q6 CHECK ENGINE COOLANT TEMPERATURE SIGNAL

- Perform powertrain control module diagnostics to check for correct operation of engine coolant temperature sensor. Refer to Powertrain Management/Computers and Control Systems/Testing and Inspection. Testing and Inspection

- Do PCM diagnostics indicate an engine coolant temperature sensor fault?

- Yes
Service as necessary. Go to Q1.

- No
Go to Q7.

Q7 CHECK CELO SIGNAL CIRCUITS FOR OPEN WIRE

- Check Wire Circuits 914 (T/O) and 915 (PK/LB) for an open circuit between the EATC control assembly and the powertrain control module.

- Are either or both circuits open?

- Yes
Service as necessary. Go to Q1.

- No
Go to Q8.

Q8 CHECK CELO CIRCUITS FOR AN INTERMITTENT OPEN

- Wiggle each wire (T/O) and (PK/LB) at each connector to check for an intermittent open.

- Does an intermittent open condition exist?

- Yes
Service as necessary. Go TO Q1.

- No
Replace EATC control assembly. Restore vehicle. Retest system.