DTC 15: Auto-cruise Control Switch System: Diagnosis

Required Special Tools: 

• MB991223: Harness Set
• MB991923: Power Plant ECU Check Harness
• MB991958: Scan Tool (MUT-III sub assembly)
  • MB991824: V.C.I.
  • MB991827: USB Cable
  • MB991910: Main Harness A

1. STEP 1. Using scan tool MB991958, check data list item 02: Set Switch. 
   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.
      Fig 1: Connecting Scan Tool To Data Link Connector

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   2. Turn the ignition switch to the "ON" position.
   3. Set scan tool MB991958 to data reading mode for auto-cruise control system.
      • Item 02: 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"
   4. Turn the ignition switch to the "LOCK" (OFF) position.
   5. Disconnect scan tool MB991958.

   Q: Is the switch operating properly? 

   1. YES  : Go to Step 2.
   2. NO  : Go to  Step 3.
2. STEP 2. Using scan tool MB991958, check data list item 03: Resume Switch. 
   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. (Refer to P.17-12).
      Fig 2: Connecting Scan Tool To Data Link Connector

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   2. Turn the ignition switch to the "ON" position.
   3. Set scan tool MB991958 to data reading mode for auto-cruise control system.
      • Item 03: 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".
   4. Turn the ignition switch to the "LOCK" (OFF) position.
   5. Disconnect scan tool MB991958.

   Q: Is the switch operating properly? 

   1. YES  : Go to  Step 17.
   2. NO  : Go to Step 3.
3. STEP 3. Measure the power supply voltage at auto-cruise control switch connector C-302 by backprobing. 
   1. Remove the air bag module (driver's side). (Refer to GROUP 52B, Air Bag Modules and Clock Spring P.52B-567).
   2. Connect the negative (-) battery cable.
   3. Do not disconnect auto-cruise control switch connector C-302.
      Fig 3: Identifying Connector C-302

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   4. Turn the ignition switch to the "ON" position and the "CRUISE" (MAIN) switch to the "OFF" position.
   5. Measure the power supply voltage between auto-cruise control switch connector C-302 terminal 2 and ground by backprobing.
      Fig 4: Measuring Power Supply Voltage

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   6. Turn the ignition switch to the "OFF" position.

   Q: Is the measured voltage between 4.7 and 5.3 volts? 

   1. YES  : Go to  Step 10.
   2. NO  : Go to Step 4.
4. STEP 4. Measure the power supply voltage at PCM connector B-18. 
   1. Disconnect all the connectors from the PCM.
      Fig 5: Disconnecting Connectors From PCM

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   2. Connect special tool MB991923 (check harness) between the PCM and the body-side harness connector.
      Fig 6: Checking Harness Between PCM And Body-Side Harness Connector

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   3. Turn the ignition switch to the "ON" position and the "CRUISE" (MAIN) switch to the "OFF" position.
   4. Measure the power supply voltage between special tool 18-pin connector terminal 12 (PCM connector B-18 terminal 12) and ground.
      Fig 7: Measuring Power Supply Voltage

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   5. Turn the ignition switch to the "OFF" position.

   Q: Is the measured voltage between 4.7 and 5.3 volts? 

   1. YES  : Go to Step 5.
   2. NO  : Go to  Step 8.
5. STEP 5. Check PCM connector B-18, intermediate connector C-31, 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. 
   Fig 8: Identifying Connector B-18

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   Fig 9: Identifying Connector C-31

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   Fig 10: Identifying Connectors: C-302, C-303, C-306

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   Q: Are the connectors and terminals in good condition? 

   1. YES  : Go to Step 6.
   2. NO  : Repair or replace the faulty connector and install the air bag module (driver's side). (Refer to DRIVER-SIDE AIR BAG MODULE & CLOCKSPRING ). Then go to  Step 18.
6. STEP 6. Check the harness wire between PCM connector B-18 terminal 12 and auto-cruise control switch connector C-302 terminal 2 for damage. 
   Fig 11: Identifying Connector B-18

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   Fig 12: Identifying Connector C-302

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   Q: Is the harness wire in good condition? 

   1. YES  : Go to Step 7.
   2. NO  : Repair the damaged harness wire, and install the air bag module (driver's side). (Refer to DRIVER-SIDE AIR BAG MODULE & CLOCKSPRING ). Then go to  Step 18.
7. STEP 7. Check the clock spring. 

   Refer to DRIVER-SIDE AIR BAG MODULE & CLOCKSPRING .

   Q: Is the clock spring in good condition? 

   1. YES  : It can be assumed that this malfunction is intermittent. (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTIONS ). Install the air bag module (driver's side). (Refer to DRIVER-SIDE AIR BAG MODULE & CLOCKSPRING ). Then go to  Step 18.
   2. NO  : Replace the clock spring and install the air bag module (driver's side). (Refer to DRIVER-SIDE AIR BAG MODULE & CLOCKSPRING ). Then go to  Step 18.
8. STEP 8. Check PCM connector B-18 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 
   Fig 13: Identifying Connector B-18

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   Q: Are the connector and terminals in good condition? 

   1. YES  : Go to Step 9.
   2. NO  : Repair or replace the faulty connector, (Refer to GROUP 00E, Harness Connector Inspection P.00E-2), and install the air bag module (driver's side). (Refer to DRIVER-SIDE AIR BAG MODULE & CLOCKSPRING ). Then go to  Step 18.
9. STEP 9. Check the harness for short circuit to ground between the PCM connector B-18 terminal 12 and the auto-cruise control switch connector C-302 terminal 2. 
   1. Disconnect PCM connector B-18 and measure at the harness connector side.
      Fig 14: Disconnecting Connector B-18

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   2. Turn the ignition switch to the "ON" position and the "CRUISE" (MAIN) switch to the "OFF" position.
   3. Measure the continuity between PCM connector B-18 terminal 12 and ground.
      Fig 15: Measuring Continuity Between PCM Connector B-18 Terminal 12 And Ground

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   4. Turn the ignition switch to the "OFF" position.

   Q: Is the measured continuity open circuit? 

   1. YES  : Install the air bag module (driver's side). (Refer to DRIVER-SIDE AIR BAG MODULE & CLOCKSPRING ). Then go to  Step 17.
   2. NO  : Repair or replace the harness wire, and install the air bag module (driver's side). (Refer to DRIVER-SIDE AIR BAG MODULE & CLOCKSPRING ). Then go to  Step 18.
10. STEP 10. 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.
       Fig 16: Identifying Connector C-302

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    2. Turn the ignition switch to the "ON" position and the "CRUISE" (MAIN) switch to the "ON" position.
    3. Measure the ground voltage between auto-cruise control switch connector C-302 terminal 3 and ground by backprobing.
       Fig 17: Measuring Ground Voltage

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    4. Turn the "CRUISE" (MAIN) switch to the "OFF" position and the ignition switch to the "OFF" position.

    Q: Is the measured voltage 0.5 volt or less? 

    1. YES  : Go to Step 11.
    2. NO  : Go to  Step 16.
11. STEP 11. Measure the power supply voltage at PCM connector B-19. 
    1. Disconnect all the connectors from the PCM.
       Fig 18: Disconnecting Connector B-19

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    2. Connect special tool MB991923 (check harness) between the PCM and the body-side harness connector.
       Fig 19: Connecting Special Tool Between PCM & Body-Side Harness Connector

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    3. Turn the ignition switch to the "ON" position and the "CRUISE" (MAIN) switch to the "ON" position.
    4. Measure the ground voltage between special tool 23-pin connector (without red tape) terminal 28 (PCM connector B-19 terminal 28) and ground.
       Fig 20: Measuring Ground Voltage Between Special Tool And Ground

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    5. Turn the "CRUISE" (MAIN) switch to the "OFF" position the ignition switch to the "OFF" position.

    Q: Is the measured voltage 0.5 volt or less? 

    1. YES  : Go to Step 12.
    2. NO  : Go to  Step 15.
12. STEP 12. Check PCM connector B-19, intermediate connector C-31, 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. 
    Fig 21: Identifying Connector B-19

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    Fig 22: Identifying Connector C-31

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    Fig 23: Identifying Connectors C-302, C-303, C-306

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    Q: Are the connectors and terminals in good condition? 

    1. YES  : Go to Step 13.
    2. NO  : Repair or replace the faulty connector and install the air bag module (driver's side). (Refer to DRIVER-SIDE AIR BAG MODULE & CLOCKSPRING ). Then go to  Step 18.
13. STEP 13. Check the harness wire between PCM connector B-19 terminal 28 and auto-cruise control switch connector C-302 terminal 3 for damage. 
    Fig 24: Identifying Connector B-19

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    Fig 25: Identifying Connectors C-302, C-303, C-306

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    Q: Is the harness wire in good condition? 

    1. YES  : Go to Step 14.
    2. NO  : Repair the damaged harness wire, and install the air bag module (driver's side). (Refer to DRIVER-SIDE AIR BAG MODULE & CLOCKSPRING ). Then go to  Step 18.
14. STEP 14. Check the clock spring. 

    Refer to DRIVER-SIDE AIR BAG MODULE & CLOCKSPRING .

    Q: Is the clock spring in good condition? 

    1. YES  : It can be assumed that this malfunction is intermittent. (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTIONS ). Install the air bag module (driver's side). (Refer to DRIVER-SIDE AIR BAG MODULE & CLOCKSPRING ). Then go to  Step 18.
    2. NO  : Replace the clock spring and install the air bag module (driver's side). (Refer to DRIVER-SIDE AIR BAG MODULE & CLOCKSPRING ). Then go to  Step 18.
15. STEP 15. Check PCM connector B-19 for loose, corroded or damaged terminals, or terminals pushed back in the connector. 
    Fig 26: Identifying Connector B-19

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    Q: Are the connector and terminals in good condition? 

    1. YES  : Install the air bag module (driver's side). (Refer to DRIVER-SIDE AIR BAG MODULE & CLOCKSPRING ). Then go to  Step 17.
    2. NO  : Repair or replace the faulty connector and install the air bag module (driver's side). (Refer to DRIVER-SIDE AIR BAG MODULE & CLOCKSPRING ). Then go to  Step 18.
16. STEP 16. Check the auto-cruise control switch. 
    1. Remove auto-cruise control switch. Refer toAUTO-CRUISE CONTROL .
    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.
       Fig 27: Checking Auto-Cruise Control Switch

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       Fig 28: Identifing Auto-Cruise Control Conditions

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    Q: Is the resistance within specifications? 

    1. YES  : Install the air bag module (driver's side). (Refer to DRIVER-SIDE AIR BAG MODULE & CLOCKSPRING ). Then go to Step 17.
    2. NO  : Replace the auto-cruise control switch, (Refer to AUTO-CRUISE CONTROL ), and install the air bag module (driver's side). (Refer to DRIVER-SIDE AIR BAG MODULE & CLOCKSPRING ). Then go to  Step 18.
17. STEP 17. Using scan tool MB991958, read the diagnostic trouble code. 
    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.
       Fig 29: Connecting Scan Tool To Data Link Connector

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    2. Turn the ignition switch to the "ON" position.
    3. Set scan tool MB991958 to read the diagnostic trouble codes.
    4. Turn the ignition switch to the "LOCK" (OFF) position.
    5. Disconnect scan tool MB991958.

    Q: Is DTC 15 set? 

    1. YES  : Replace the PCM. [Refer to POWERTRAIN CONTROL MODULE (PCM) ]. Then go to Step 18.
    2. NO  : It can be assumed that this malfunction is intermittent. (Refer to HOW TO COPE WITH INTERMITTENT MALFUNCTIONS ).
18. Step 18. Using scan tool MB991958, read the diagnostic trouble code. 
    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.
       Fig 30: Connecting Scan Tool To Data Link Connector

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    2. Turn the ignition switch to the "ON" position.
    3. Set scan tool MB991958 to read the diagnostic trouble codes.
    4. Turn the ignition switch to the "LOCK" (OFF) position.
    5. Disconnect scan tool MB991958.

    Q: Is DTC 15 set? 

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