DIAGNOSIS Required Special Tool: • MB991958: Scan Tool (MUT-III Sub Assembly) MB991824: V.C.I. MB991827: MUT-III USB Cable MB991911: MUT-III Main Harness B

STEP 1. Using scan tool MB991958, check data list item 54: A/T Control Relay Output Voltage.

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) Set scan tool MB991958 to the data reading mode. Item 54: A/T Control Relay Output Voltage. The voltage should equal battery positive voltage. (4) Turn the ignition switch to the "LOCK" (OFF) position. Q: Is the measured voltage equal battery positive voltage? YES: 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 Malfunction . NO: Go to Step 2 .

STEP 2. Check the A/T control relay.

(1) Remove the A/T control relay from the engine component relay box connector B-11X.

(2) Using jumper wires, connect terminal 2 to the positive battery terminal, and terminal 3 to the negative battery terminal. (3) Measure the resistance between terminals 1 and 4 of the A/T control relay. • The resistance should be measured less than 2 ohms. • Disconnect the jumper wires. The resistance between terminals 1 and 4 should measure over limits (open circuit). Q: Is the measured resistance less than 2 ohms when the relay is energized, and open circuit when the relay is de-energized? YES: Go to Step 3 . NO: Replace the A/T control relay.

STEP 3. Check A/T control relay socket B-11X in the engine compartment relay box for loose, corroded or damaged terminals, or terminals pushed back in the socket.

Q: Is the relay connector in good condition? YES: Go to Step 4 . NO: Repair or replace the damaged components. Refer to GROUP 00E, Harness Connector Inspection .

STEP 4. Measure the supply voltage at A/T control relay connector B-11X in the engine component relay box.

(1) Disconnect the A/T control relay.

(2) Measure the voltage between terminal 1 and ground. The measured voltage should equal battery positive voltage. Q: Is the measured voltage equal to battery positive voltage? YES: Go to Step 7 . NO: Go to Step 5 .

STEP 5. Check intermediate connector A-13 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are the connector and terminals in good condition? YES: Go to Step 6 . NO: Repair or replace the damaged components. Refer to GROUP 00E, Harness Connector Inspection .

STEP 6. Check the harness for open circuit or short circuit to ground between A/T control relay connector B-11X terminal 1 in the engine component relay box and battery.

Q: Is the harness wire in good condition? YES: Go to Step 15 . NO: Repair or replace the harness wire.

STEP 7. Measure the supply voltage at A/T control relay connector B-11X in the engine component relay box.

(1) Disconnect the A/T control relay. (2) Turn the ignition switch to the "ON" position.

(3) Measure the voltage between terminal 2 and ground. The measured voltage should equal battery positive voltage. (4) Turn the ignition switch to the "LOCK" (OFF) position. Q: Is the measured voltage equal to battery positive voltage? YES: Go to Step 10 . NO: Go to Step 8 .

STEP 8. Check intermediate connector C-123 and junction block connector C-210 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are the connectors in good condition? YES: Go to Step 9 . NO: Repair or replace the damaged components. Refer to GROUP 00E, Harness Connector Inspection .

STEP 9. Check the harness for open circuit or short circuit to ground between A/T control relay connector B-11X terminal 2 in the engine component relay box and junction block connector C-210 terminal 12.

Q: Is the harness wire in good condition? YES: Go to Step 15 . NO: Repair or replace the harness wire.

STEP 10. Measure the A/T control relay output voltage at PCM connector C-116 by backprobing.

(1) Do not disconnect connector C-116. (2) Turn the ignition switch to the "ON" position.

(3) Measure the voltage between terminal 77 and ground. The measured voltage should equal battery positive voltage.

(4) Measure the voltage between terminal 89 and ground. The measured voltage should equal battery positive voltage. (5) Turn the ignition switch to the "LOCK" (OFF) position. Q: Is the measured voltage equal to battery positive voltage between terminal 77 and ground, and between terminal 89 and ground? YES: Go to Step 13 . NO: Go to Step 11 .

STEP 11. Check PCM connector C-116 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are the connector and terminals in good condition? YES: Go to Step 12 . NO: Repair or replace the damaged components. Refer to GROUP 00E, Harness Connector Inspection .

STEP 12. Check harness for open circuit or short circuit to ground between A/T control relay connector B-11X (terminal 4) in the engine component relay box and PCM connector C-116 (terminals 77 and 89).

Q: Is the harness wire in good condition? YES: Go to Step 15 . NO: Repair or replace the harness wire.

STEP 13. Check PCM connector C-118 for loose, corroded or damaged terminals, or terminals pushed back in the connector.

Q: Are the connector and terminals in good condition? YES: Go to Step 14 . NO: Repair or replace the damaged components. Refer to GROUP 00E, Harness Connector Inspection .

STEP 14. Check harness for open circuit or short circuit to ground between A/T control relay connector B-11X terminal 3 in the engine component relay box and PCM connector C-118 terminal 50.

Q: Is the harness wire in good condition? YES: Go to Step 15 . NO: Repair or replace the harness wire.