Code No.P1564:
Abnormal voltage at cruise control switches.
OPERATION
This circuit judges the signals of each switches (speed limiter ON/OFF, cruise
control ON/OFF, CANCEL, SET - and RES +) of the cruise control switch.
The engine-ECU detects the state of the cruise control switches by sensing the voltages shown
below.
- When all switches are released: 4.7 - 5.0 volts
- When the speed limiter ON/OFF switch is pressed: 0 - 0.5 volts <vehicles
with speed limiter>
- When the cruise control ON/OFF switch is pressed: 0.9 - 1.7 volt
- When the CANCEL switch is pressed: 1.9 - 2.7 volts
- When the SET - switch is pressed: 2.9 - 3.6 volts
- When the RES + switch is pressed: 3.8 - 4.5 volts
DIAGNOSIS CODE SET CONDITIONS
- If the cruise control switches is operated, this diagnosis
code will be set when the engine-ECU terminal voltage is different from the standard value.
- Or, this code is set when the SET - switch or RES + switch is
stuck to ON.
PROBABLE CAUSES
- Damaged harness or connector.
- Malfunction of the cruise control switch.
- Malfunction of the clock spring.
- Malfunction of the engine-ECU.
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STEP 1. Check the data list.
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Using M.U.T.-III, check the data list (Refer to data list reference table ).
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- Item 136: Cruise control ON/OFF switch.
- Item 137: Cruise cancel switch.
- Item 138: Cruise set switch.
- Item 139: Cruise resume switch.
- Item 460: Speed limiter ON/OFF switch <Vehicles with speed limiter>.
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Q.
Is the check result normal?
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Go to Step 19.
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Go to Step 2.
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STEP 2. Measure the terminal voltage at cruise control switch connector.
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(1)Remove the cruise control switch from the steering wheel with the cruise control
switch connector connected (Refer to ).
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(2)Connect the negative battery terminal that was disconnected when the driver’s
air bag module was removed.
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(3)Turn the ignition switch to the "ON" position.
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(4)Do not operate the cruise control switch.
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(5)Measure the terminal voltage between cruise control switch connector terminal engine-ECU
CNTS line and earth with cruise control switch connector connected. OK: 4.7 - 5.0 V
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Q.
Is the check result normal?
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Go to Step 11.
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Go to Step 3.
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STEP 3. Measure the terminal voltage at engine-ECU connector.
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(1)Remove the engine-ECU (Refer to GROUP 13B - Engine-ECU <4D5>,
GROUP 13C - Engine-ECU <4N1>).
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(2)Connect special tool power plant ECU check harness (MB992291) between the engine-ECU
and the body-side harness connector.
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(3)Turn the ignition switch to the "ON" position.
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(4)Do not operate the cruise control switch.
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(5)Measure the terminal voltage between special tool 58-pin connector terminal No.139
(engine-ECU connector terminal CNTS) and earth. OK: 4.7 - 5.0 V
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Q.
Is the check result normal?
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Go to Step 8.
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Go to Step 4.
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STEP 4. Check the harness wire for short circuit to earth between
engine-ECU connector terminal CNTS and the cruise control switch connector terminal.
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(1)Check the engine-ECU connector.
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(2)Disconnect engine-ECU connector and measure at the harness connector side.
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(3)Turn the ignition switch to the "LOCK" (OFF) position.
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(4)Measure the continuity between engine-ECU connector terminal CNTS and earth. OK: open circuit
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Q.
Is the check result normal?
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Go to Step 18.
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Go to Step 5.
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STEP 5. Check the harness wire between engine-ECU connector terminal
CNTS and clock spring connector terminal, and between clock spring connector terminal and cruise
control switch connector terminal.
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- Check connector or harness wire for short circuit and damage.
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Q.
Is the check result normal?
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Go to Step 6.
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Repair connector or damaged harness wire. Then go to Step 20.
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STEP 6. Check the clock spring.
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Refer to GROUP 52B - Driver’s Air Bag Module and Clock Spring Inspection .
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Q.
Is the check result normal?
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Go to Step 7.
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Replace the clock spring and install the driver’s air bag module (Refer
to GROUP 52B - Driver’s Air Bag Module and Clock Spring ).
Then go to Step 20.
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STEP 7. Check the cruise control switches.
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Refer to .
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Q.
Is the check result normal?
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Go to Step 10.
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Replace the cruise control switches (Refer to ). Then
go to Step 20.
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STEP 8. Check the harness wire between engine-ECU connector terminal
CNTS and clock spring connector terminal, and between clock spring connector terminal and cruise
control switch connector terminal.
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- Check connector or harness wire for open circuit and damage.
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Q.
Is the check result normal?
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Go to Step 9.
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Repair connector or damaged harness wire. Then go to Step 20.
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STEP 9. Check the clock spring.
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Refer to GROUP 52B - Driver’s Air Bag Module and Clock Spring Inspection .
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Q.
Is the check result normal?
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Go to Step 10.
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Replace the clock spring and install the driver’s air bag module (Refer
to GROUP 52B - Driver’s Air Bag Module and Clock Spring ).
Then go to Step 20.
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STEP 10. Check the data list.
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Using M.U.T.-III, check the data list (Refer to data list reference table ).
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- Item 136: Cruise control ON/OFF switch.
- Item 137: Cruise cancel switch.
- Item 138: Cruise set switch.
- Item 139: Cruise resume switch.
- Item 460: Speed limiter ON/OFF switch <Vehicles with speed limiter>.
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Q.
Is the check result normal?
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Go to Step 19.
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Go to Step 11.
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STEP 11. Measure the terminal voltage at cruise control switch connector.
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(1)Remove the cruise control switch from the steering wheel with the cruise control
switch connector connected (Refer to ).
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(2)Turn the ignition switch to the "ON" position.
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(3)Press the cruise control ON/OFF switch with cruise control switch connector
connected, and measure the terminal voltage between cruise control switch connector terminal engine-ECU
SW- line and earth. OK: 0.9 - 1.7 V
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Q.
Is the check result normal?
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Go to Step 15.
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Go to Step 12.
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STEP 12. Measure the terminal voltage at engine-ECU connector.
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(1)Remove the engine-ECU (Refer to GROUP 13B - Engine-ECU <4D5>,
GROUP 13C - Engine-ECU <4N1>).
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(2)Connect special tool power plant ECU check harness (MB992291) between the engine-ECU
and the body-side harness connector.
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(3)Turn the ignition switch to the "ON" position.
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(4)Press the cruise control ON/OFF switch, and measure the terminal voltage
between special tool 58-pin connector terminal No.154 (engine-ECU connector terminal SW-)
and earth. OK: 0.9 - 1.7 V
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Q.
Is the check result normal?
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Go to Step 13.
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Go to Step 18.
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STEP 13. Check the harness wire between engine-ECU connector terminal
SW- and clock spring connector terminal, and between clock spring connector terminal
and cruise control switch connector terminal.
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- Check connector or harness wire for open circuit and damage.
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Q.
Is the check result normal?
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Go to Step 14.
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Repair connector or damaged harness wire. Then go to Step 20.
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STEP 14. Check the clock spring.
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Refer to GROUP 52B - Driver’s Air Bag Module and Clock Spring Inspection .
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Q.
Is the check result normal?
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Go to Step 18.
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Replace the clock spring and install the driver’s air bag module (Refer
to GROUP 52B - Driver’s Air Bag Module and Clock Spring ).
Then go to Step 20.
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STEP 15. Check the harness wire between engine-ECU connector terminal
SW- and clock spring connector terminal, and between clock spring connector terminal
and cruise control switch connector terminal.
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- Check connector or harness wire for short circuit and damage.
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Q.
Is the check result normal?
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Go to Step 16.
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Repair connector or damaged harness wire. Then go to Step 20.
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STEP 16. Check the clock spring.
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Refer to GROUP 52B - Driver’s Air Bag Module and Clock Spring Inspection .
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Q.
Is the check result normal?
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Go to Step 17.
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Replace the clock spring and install the driver’s air bag module (Refer
to GROUP 52B - Driver’s Air Bag Module and Clock Spring ).
Then go to Step 20.
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STEP 17. Check the cruise control switches.
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Refer to .
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Q.
Is the check result normal?
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Go to Step 18.
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Replace the cruise control switches (Refer to ). Then
go to Step 20.
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STEP 18. Check the data list.
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Using M.U.T.-III, check the data list (Refer to data list reference table ).
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- Item 136: Cruise control ON/OFF switch.
- Item 137: Cruise cancel switch.
- Item 138: Cruise set switch.
- Item 139: Cruise resume switch.
- Item 460: Speed limiter ON/OFF switch <Vehicles with speed limiter>.
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Q.
Is the check result normal?
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Go to Step 19.
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Replace the engine-ECU (Refer to GROUP 13B - Engine-ECU <4D5>,
GROUP 13C - Engine-ECU <4N1>). Then
go to Step 20.
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STEP 19. Read the diagnosis code.
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(1)Use the M.U.T.-III, erase the diagnosis code of the cruise control system.
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(2)Turn the ignition switch to the "ON" position, and press the cruise control ON/OFF
switch to turn the cruise control system to ON (the cruise control indicator lamp is turned on).
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(3)After turning the cruise control system to ON, when 2 minutes or more has elapsed
without operating the cruise control switches, read the diagnosis code of the cruise control
system.
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Q.
Is diagnosis code No.P1564 set?
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Replace the engine-ECU (Refer to GROUP 13B - Engine-ECU <4D5>,
GROUP 13C - Engine-ECU <4N1>). Then
go to Step 20.
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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 ).
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STEP 20. Check the data list.
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Using M.U.T.-III, check the data list (Refer to data list reference table ).
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- Item 136: Cruise control ON/OFF switch.
- Item 137: Cruise cancel switch.
- Item 138: Cruise set switch.
- Item 139: Cruise resume switch.
- Item 460: Speed limiter ON/OFF switch <Vehicles with speed limiter>.
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Q.
Is the check result normal?
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Go to Step 21.
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Return to Step 2.
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STEP 21. Read the diagnosis code.
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(1)Use the M.U.T.-III, erase the diagnosis code of the cruise control system.
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(2)Turn the ignition switch to the "ON" position, and press the cruise control ON/OFF
switch to turn the cruise control system to ON (turn ON the cruise control indicator lamp).
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(3)After turning the cruise control system to ON, when 2 minutes or more has elapsed
without operating the cruise control switches, read the diagnosis code of the cruise control
system.
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Q.
Is diagnosis code No.P1564 set?
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Return to Step 1.
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The procedure is complete.
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