STEP 1. Using scan tool MB991958, diagnose the CAN bus line
(1) 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. |
Connect scan tool MB991958. Refer to "How to connect the Scan Tool (M.U.T.-III)
."
(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.
Is the CAN bus line found to be normal?
Go to Step 2. Repair the CAN bus line. (Refer to GROUP 54C, Diagnosis ).
STEP 2. Recheck for diagnostic trouble code.
Recheck if the DTC is set.(1) Erase the DTC.
(2) Turn the ignition switch to "ON" position.
(3) Check if the DTC is set.
Is the DTC set?
Go to Step 3. It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions .
STEP 3. Check A/C pressure sensor connector A-63 and A/C control panel connector C-216 for loose, corroded or damaged terminals, or terminals pushed back in the connector.
STEP 4. Check the wiring harness between A/C control panel connector C-216 (terminals 12, 11 and 6) and A/C pressure sensor connector A-63 (terminals 3, 2 and 1).
STEP 5. Check the A/C pressure sensor operation.
(1) Assemble a gauge manifold on the high pressure service valve.
(2) Disconnect the A/C pressure sensor connector and connect special tool test harness MB991658 as shown in the illustration.
(3) Turn ON the engine and then turn ON the A/C switch.
(4) At this time, check to see that the voltage of A/C pressure sensor terminal No. 2 reflects the specifications of the figure.note | The allowance shall be defined as ±5%. |
Is the A/C pressure sensor operating properly?
Go to Step 6. Replace the A/C pressure sensor. Then go to Step 7.
STEP 6. Check the refrigerant level.
STEP 7. Recheck for diagnostic trouble code.
Check again if the 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.
Is the DTC set?
Return to Step 1. The procedure is complete.