Inspection Procedure 7

INSPECTION PROCEDURE 7: The condenser fan and the radiator fan turn at full speed.


















FUNCTION

The condenser turns the high-temperature and high-pressure refrigerant into liquid by cooling it down with fresh air, and it is cooled down by the air from the condenser fan.

PROBABLE CAUSES

- Malfunction of connector.
- Malfunction of the harness (Pressure sensor circuit is open)
- Malfunction of the A/C pressure sensor.
- Malfunction of the condenser fan motor.
- Malfunction of the A/C-ECU.

DIAGNOSIS

Required Special Tools:

- MB991223: Harness Set
- MB992006: Extra Fine Probe
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A

STEP 1. Using scan tool MB991958, diagnose the CAN bus line.





CAUTION:
To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK"
(OFF) position before connecting or disconnecting scan tool MB991958.

(1)Connect scan tool MB991958 to the data link connector.
(2)Turn the ignition switch to the "ON" position.
(3)Diagnose the CAN bus line.
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the CAN bus line found to be normal?

YES Go to Step 2.

NO Repair the CAN bus lines Precautions on How to Repair the CAN Bus Line(s)).

STEP 2. Using scan tool MB991958, read the diagnostic trouble code.

Check if an A/C-ECU DTC is set.

(1)Connect scan tool MB991958 to the data link connector.

(2)Turn the ignition switch to the "ON" position.

(3)Check if the DTC is set.

(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the check result satisfactory?

YES Refer to Diagnostic Trouble Code Chart Automatic Air Conditioning.
NO Go to Step 3.
STEP 3. Using scan tool MB991958 read the ECM [M/T] or PCM [A/T] diagnostic trouble code.

Check whether an engine and automatic transaxle DTCs are set or not.

(1)Turn the ignition switch to the "ON" position.

(2)Check for engine and automatic transaxle DTCs.

(3)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the check result satisfactory?

YES Go to Step 4.
NO Diagnose the powertrain control module Multiport Fuel Injection (MFI) [3.8L ENGINE]).
STEP 4. Using scan tool MB991958, check actuator test.

(1)Connect scan tool MB991958 to the data link connector.

(2)Start the engine.

(3)Use scan tool MB991958 to run the actuator test.

- Item 77: Condenser fan: 0%
- Item 78: Condenser fan: 100%
- Item 79: Condenser fan: 50%
- Check that the condenser fan motor operates.

(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Does the motor operate normally?

YES Go to Step 5.
NO Go to Step 6.
STEP 5. Retest the system.

Check the trouble symptom again.

Q. Is the check result satisfactory?

YES It can be assumed that this malfunction is intermittent. How to Cope With Intermittent Malfunctions.
NO Replace the A/C-ECU.
STEP 6. Check the condenser fan motor operation.





When battery voltage is applied between the terminals, check that the motor operates.
Also, check that there is no abnormal noise.

Q. Is there any abnormal noise?

YES Go to Step 7.

NO Diagnose the ECM [M/T] or PCM [A/T] Symptom Chart [3.8L ENGINE]).

STEP 7. Check A/C pressure sensor connector A-34 for loose, corroded or damaged terminals, or terminals pushed back in the connector.





Q. Is A/C pressure sensor connector A-34 in good condition?

YES Go to Step 8.

NO Repair or replace the connector. Harness Connector Inspection.

STEP 8. Check the wiring harness for open circuit.









(1)Disconnect A/C-ECU connector C-20 and A/C pressure sensor connector A-34, and measure the resistance at the wiring harness side.





(2)Measure the resistance between A/C-ECU connector C-20 terminal 34 and A/C pressure sensor connector A-34 terminal 1.
OK: Less than 2 ohms

Q. Is the check result normal?

YES Go to Step 10.

NO Go to Step 9.

STEP 9. Check the wiring harness between A/C-ECU connector C-20 (terminal 34) and A/C pressure sensor connector A-34 (terminal 1).













NOTE:
Also check intermediate connector C-24 for loose, corroded, or damaged terminals, or terminals pushed back in the connector. If intermediate connector C-24 is damaged, repair or replace the connector as described in Harness Connector Inspection Harness Connector Inspection.

Q. Is the wiring harness between A/C-ECU connector C-20 (terminal 34) and A/C pressure sensor connector A-34 (terminal 1) in good condition?

YES It can be assumed that this malfunction is intermittent. How to Cope With Intermittent Malfunctions.

NO Repair the wiring harness.

STEP 10. Retest the system.

Check that the condenser works normally.

Q. Is the check result satisfactory?

YES It can be assumed that this malfunction is intermittent. How to Cope With Intermittent Malfunctions.
NO Replace the A/C-ECU.