DTC 15

DTC 15: Auto-cruise Control Switch System

















CIRCUIT OPERATION

This circuit judges the signals of each switch ("COAST/SET", "ACC/RES"
and "CANCEL") of the auto-cruise control switch. The ECM [M/T] or PCM [A/T] detects the state of the auto-cruise control switch by sensing the voltages shown below.

- When all switches are OFF: 4.7 - 5.0 volts
- When the "CRUISE" (MAIN) switch is "ON": 0 - 0.3 volt
- When the "COAST/SET" switch is ON: 2.0 - 2.8 volts
- When the "ACC/RES" switch is ON: 3.3 - 4.1 volts
- When the "CANCEL" switch is ON: 0.8 - 1.5 volts


DTC SET CONDITIONS

Check Condition

- The "CRUISE" indicator light illuminates.
Judgement Criteria

- If the auto-cruise control switch is operated, this DTC will be set when the ECM[ M/T] or PCM[ A/T] terminal voltage is different from the standard value.

TROUBLESHOOTING HINTS (THE MOST LIKELY CAUSES FOR THIS CASE:)

- Malfunction of the auto-cruise control switch.
- Malfunction of the clock spring.
- Damaged harness or connector.
- Malfunction of the ECM[ M/T] or PCM[ A/T].

DIAGNOSIS

Required Special Tools:

- 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
- MB991223: Harness Set
- MB992006: Extra Fine Probe
- MB991923: Power Plant ECU Check Harness

STEP 1. Using scan tool MB991958, check data list item 86: Main switch, list item 92: Set switch, item 91: Resume switch and list item 75: Cancel switch.





(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 to the data link connector. (Refer to Reading and Clearing Diagnostic Trouble Codes).
(2)Turn the ignition switch to the "ON" position.
(3)Set scan tool MB991958 to data reading mode for auto-cruise control system. (Refer to Scan Tool Testing and Procedures).

- Item 86: Main switch.
- When "CRUISE" (MAIN) switch is at the "ON" position, the display on scan tool MB991958 should be "ON".
- When "CRUISE" (MAIN) switch is at the "OFF" position, the display on scan tool MB991958 should be "OFF".

- Item 92: Set switch.
- When "COAST/SET" switch is at the "ON" position, the display on scan tool MB991958 should be "ON".
- When "COAST/SET" switch is at the "OFF" position, the display on scan tool MB991958 should be "OFF".

- Item 91: Resume switch.
- When "ACC/RES" switch is at the "ON" position, the display on scan tool MB991958 should be "ON".
- When "ACC/RES" switch is at the "OFF" position, the display on scan tool MB991958 should be "OFF".

- Item 75: Cancel switch.
- When "CANCEL" switch is at the "ON" position, the display on scan tool MB991958 should be "ON".
- When "CANCEL" switch is at the "OFF" position, the display on scan tool MB991958 should be "OFF".
(4)Turn the ignition switch to the "LOCK" (OFF) position.
(5)Disconnect scan tool MB991958.

Q. Is the switch operating properly?

YES Go to Step 17.

NO Go to Step 2.

STEP 2. Measure the power supply voltage at auto-cruise control switch connector C-302 by backprobing.

(1)Remove the air bag module (driver's side). Service and Repair).

(2)Connect the negative (-) battery cable.





(3)Do not disconnect auto-cruise control switch connector C-302.
(4)Turn the ignition switch to the "ON" position.
(5)The "CRUISE" (MAIN) switch to the "OFF" position.





(6)Measure the power supply voltage between auto-cruise control switch connector C-302 terminal 2 and ground by backprobing.
(7)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the measured voltage between 4.7 and 5.0 volts?

YES Go to Step 9.

NO Go to Step 3.

STEP 3. Measure the power supply voltage at ECM [M/T] or PCM [A/T] connector B-18.





(1)Disconnect all the connectors from the ECM [M/T] or PCM [A/T].





(2)Connect special tool MB991923 between the ECM [M/T] or PCM [A/T] and the body-side harness connector.
(3)Turn the ignition switch to the "ON" position.
(4)The "CRUISE" (MAIN) switch to the "OFF" position.





(5)Measure the power supply voltage between special tool 18-pin connector terminal 12 (ECM [M/T] or PCM [A/T] connector B-18 terminal 12) and ground.
(6)Turn the ignition switch to the "LOCK" (OFF) position.
(7)Disconnect special tool MB991923 between the ECM [M/T] or PCM [A/T] and the body-side harness connector.
(8)Reconnect all the connectors to the ECM [M/T] or PCM [A/T].

Q. Is the measured voltage between 4.7 and 5.0 volts?

YES Go to Step 6.

NO Go to Step 4.

STEP 4. Check ECM [M/T] or PCM [A/T] connector B-18 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 5.

NO Repair or replace the faulty connector. Harness Connector Inspection). Install the air bag module (driver's side). Service and Repair).
Then go to Step 18.

STEP 5. Check the harness for short circuit to ground between the ECM [M/T] or PCM [A/T] connector B-18 terminal 12 and the auto-cruise control switch connector C-302 terminal 2.





(1)Disconnect ECM [M/T] or PCM [A/T] connector B-18 and measure at the harness connector side.
(2)Turn the ignition switch to the "LOCK" (OFF) position.





(3)Measure the continuity between ECM [M/T] or PCM [A/T] connector B-18 terminal 12 and ground.
(4)Reconnect ECM [M/T] or PCM [A/T] connector B-18.

Q. Is the measured continuity open circuit?

YES Install the air bag module (driver's side). Service and Repair). Then go to Step 17.

NO Go to Step 6.

STEP 6. Check intermediate connector C-24, auto-cruise control switch connector C-302 and clock spring connectors C-303 and C-306 for loose, corroded or damaged terminals, or terminals pushed back in the connector.









Q. Are the connectors and terminals in good condition?

YES Go to Step 7.

NO Repair or replace the faulty connector. Harness Connector Inspection). Install the air bag module (driver's side). Service and Repair).
Then go to Step 18.

STEP 7. Check the harness wire between ECM [M/T] or PCM [A/T] connector B-18 terminal 12 and auto-cruise control switch connector C-302 terminal 2 for damage.









Q. Are the harness wires in good condition?

YES Go to Step 8.

NO Repair the damaged harness wire and install the air bag module (driver's side). Service and Repair).
Then go to Step 18.

STEP 8. Check the clock spring.

Inspection.

Q. Is the clock spring in good condition?

YES It can be assumed that this malfunction is intermittent. How to Cope With Intermittent Malfunctions). Install the air bag module (driver's side). Service and Repair).
Then go to Step 18.
NO Replace the clock spring and install the air bag module (driver's side).
Service and Repair). Then go to Step 18.
STEP 9. Measure the ground voltage at auto-cruise control switch connector C-302 by backprobing.





(1)Do not disconnect auto-cruise control switch connector C-302.
(2)Turn the ignition switch to the "ON" position.
(3)Turn the "CRUISE" (MAIN) switch to the "ON" position.





(4)Measure the ground voltage between auto-cruise control switch connector C-302 terminal 3 and ground by backprobing.
(5)Turn the "CRUISE" (MAIN) switch to the "OFF" position.
(6)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the measured voltage 0.5 volt or less?

YES Go to Step 15.

NO Go to Step 10.

STEP 10. Measure the ground voltage at ECM [M/T] or PCM [A/T] connector B-19.





(1)Disconnect all the connectors from the ECM [M/T] or PCM [A/T].





(2)Connect special tool MB991923 between the ECM [M/T] or PCM [A/T] and the body-side harness connector.
(3)Turn the ignition switch to the "ON" position.
(4)Turn the "CRUISE" (MAIN) switch to the "ON" position.





(5)Measure the ground voltage between special tool 23-pin connector (without red tape) terminal 28 (ECM [M/T] or PCM [A/T] connector B-19 terminal 28) and ground.
(6)Turn the "CRUISE" (MAIN) switch to the "OFF" position.
(7)Turn the ignition switch to the "LOCK" (OFF) position.
(8)Disconnect special tool MB991923 between the ECM [M/T] or PCM [A/T] and the body-side harness connector.
(9)Reconnect all the connectors to the ECM [M/T] or PCM [A/T].

Q. Is the measured voltage 0.5 volt or less?

YES Go to Step 12.

NO Go to Step 11.

STEP 11. Check ECM [M/T] or PCM [A/T] connector B-19 for loose, corroded or damaged terminals, or terminals pushed back in the connector.





Q. Are the connector and terminals in good condition?

YES Install the air bag module (driver's side). Service and Repair). Then go to Step 17.

NO Repair or replace the faulty connector. Harness Connector Inspection). Install the air bag module (driver's side). Service and Repair).
Then go to Step 18.

STEP 12. Check ECM [M/T] or PCM [A/T] connector B-19, intermediate connector C-24, auto-cruise control switch connector C-302 and clock spring connectors C-303 and C-306 for loose, corroded or damaged terminals, or terminals pushed back in the connector.













Q. Are the connectors and terminals in good condition?

YES Go to Step 13.

NO Repair or replace the faulty connector. Harness Connector Inspection). Install the air bag module (driver's side). Service and Repair).
Then go to Step 18.

STEP 13. Check the harness wire between ECM [M/T] or PCM [A/T] connector B-19 terminal 28 and auto-cruise control switch connector C-302 terminal 3 for damage.









Q. Are the harness wires in good condition?

YES Go to Step 14.

NO Repair the damaged harness wire and install the air bag module (driver's side). Service and Repair).
Then go to Step 18.

STEP 14. Check the clock spring.

Inspection.

Q. Is the clock spring in good condition?

YES It can be assumed that this malfunction is intermittent. How to Cope With Intermittent Malfunctions). Install the air bag module (driver's side). Service and Repair).
Then go to Step 18.
NO Replace the clock spring and install the air bag module (driver's side).
Service and Repair). Then go to Step 18.
STEP 15. Check auto-cruise control switch connector C-302 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 16.

NO Repair or replace the faulty connector. Harness Connector Inspection). Install the air bag module (driver's side). Service and Repair).
Then go to Step 18.

STEP 16. Check the auto-cruise control switch.

(1)Remove the steering wheel assembly. Service and Repair).





(2)Measure the resistance between terminal 2 and terminal 3 when each of the "CRUISE" (MAIN),
"COAST/SET", "ACC/RES" and "CANCEL" switch is pressed.





Q. Is the resistance within specifications?

YES Install the air bag module (driver's side). Service and Repair). Then go to Step 17.

NO Replace the auto-cruise control switch. (Refer to Service and Repair).
Install the air bag module (driver's side). Service and Repair). Then go to Step 18.

STEP 17. Read the diagnostic trouble code.

Read the diagnostic trouble codes. (Refer to Reading and Clearing Diagnostic Trouble Codes).

Q. Is DTC 15 set?

YES Replace the ECM [M/T] or PCM [A/T]. Encrypted Code Registration Criteria Table). Then go to Step 18.
NO It can be assumed that this malfunction is intermittent. How to Cope With Intermittent Malfunctions).
STEP 18. Read the diagnostic trouble code.

Read the diagnostic trouble codes. (Refer to Reading and Clearing Diagnostic Trouble Codes).

Q. Is DTC 15 set?

YES Return to Step 1.
NO The procedure is complete.