Cruise Control (Diagnostic Codes & Circuit Tests): Overview Lexus LX J200

DESCRIPTION

The speed sensor detects the wheel speed and sends the appropriate signals to the master cylinder solenoid (skid control ECU). The master cylinder solenoid (skid control ECU) converts these wheel speed signals into a 4-pulse signal and outputs it to the ECM via the combination meter. The ECM determines the vehicle speed based on the frequency of these pulse signals.

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If a malfunction (a rapid change in vehicle speed) in the vehicle speed signal being output from the master cylinder solenoid (skid control ECU) is detected while the cruise control is in operation, the ECM determines there to be a momentary interruption and noise, and outputs a DTC.

When the brake pedal is depressed, the stop light switch sends a signal to the ECM. When the ECM receives this signal, it cancels the cruise control. The fail-safe function operates to enable normal driving even if there is a malfunction in the stop light signal circuit. The cancellation condition occurs when voltage is applied to terminal STP. When the brake is applied, voltage is applied to terminal STP of the ECM through the STOP fuse and the stop light switch, and the ECM turns the cruise control off.

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1. READ VALUE USING TECHSTREAM (STOP LIGHT SWITCH) Using the Techstream, read the Data List. CRUISE CONTROL Tester Display Measurement Item/Range Normal Condition Diagnostic Note Stop Light SW M-CPU Stop light switch signal (Main CPU) / ON or OFF ON: Brake pedal depressed OFF: Brake pedal released - OK Normal conditions listed above are displayed. NG --> See step 2 OK --> See step 5
2. INSPECT STOP LIGHT SWITCH Remove the stop light switch. Refer to «REMOVAL»(ref-385213-S23013949742011021400000) . Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Switch Condition Specified Condition 1 - 2 Pin pushed 10 kohms or higher Pin not pushed Below 1 ohms 3 - 4 Pin pushed Below 1 ohms Pin not pushed 10 kohms or higher NG --> See step 6 OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (BATTERY - STOP LIGHT SWITCH) Disconnect the A30 stop light switch connector. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition A30-2 - Body ground Always 11 to 14 V A30-3 - Body ground Engine switch on (IG) NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
4. CHECK HARNESS AND CONNECTOR (STOP LIGHT SWITCH - ECM) Disconnect the A30 stop light switch connector. Disconnect the A38 ECM connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A30-1 - A38-36 (STP) Always Below 1 ohms A30-1 - Body ground Always 10 kohms or higher A30-4 - A38-35 (ST1-) Always Below 1 ohms A30-4 - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 5
5. REPLACE ECM. Refer to «REMOVAL»(ref-385180-S10778133792011021400000)
6. REPLACE STOP LIGHT SWITCH. Refer to «REMOVAL»(ref-385213-S23013949742011021400000)

This DTC indicates internal abnormalities of the ECM.

HINT

If DTC P0575 is stored while the cruise control is in operation, the master cylinder solenoid (skid control ECU) clears the stored vehicle speed in the ECM and cancels the cruise control operation. At the same time, the CRUISE main indicator light blinks to inform the driver of the malfunction. When this trouble code is stored, fail-safe remains on until the engine switch is turned off.

The cruise control main switch is used to operate 7 functions: SET, - (COAST), TAP-DOWN, RES (RESUME), + (ACCELERATION), TAP-UP, and CANCEL. The SET, TAP-DOWN and - (COAST) functions, and the RES (RESUME), TAP-UP and + (ACCELERATION) functions are operated with the same switch. The cruise control main switch is an automatic return type switch which turns on only while operating it in each arrow direction and turns off after releasing it. The internal contact point of the cruise control main switch is turned on with the switch operation. Then the ECM reads the resistance value that has been changed by the switch operation to control SET, - (COAST), RES (RESUME), + (ACCELERATION) and CANCEL.

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1. READ VALUE USING TECHSTREAM (CRUISE CONTROL MAIN SWITCH) Using the Techstream, read the Data List. CRUISE CONTROL Tester Display Measurement Item/Range Normal Condition Diagnostic Note CCS Main SW M-CPU Cruise control main switch (Main CPU) / ON or OFF ON: Cruise control main switch (Main CPU) on OFF: Cruise control main switch (Main CPU) off - Cancel Switch CANCEL switch signal / ON or OFF ON: CANCEL switch on OFF: CANCEL switch off - SET/COAST Switch -SET switch signal / ON or OFF ON: -SET switch on OFF: -SET switch off - RES/ACC Switch +RES switch signal / ON or OFF ON: +RES switch on OFF: +RES switch off - CCS Main SW S-CPU Cruise control main switch (Sub CPU) / ON or OFF ON: Cruise control main switch (Sub CPU) on OFF: Cruise control main switch (Sub CPU) off - OK The Techstream display changes according to operation of cruise control main switch. NG --> See step 2 OK --> See step 7
2. INSPECT CRUISE CONTROL MAIN SWITCH Remove the cruise control main switch. Refer to «REMOVAL»(ref-385227-S07773173762011021400000) . Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Switch Condition Specified Condition 1 - 3 Neutral 1 Mohms or higher Pushed to +RES 235 to 245 ohms Pushed to -SET 620 to 640 ohms Pushed to CANCEL 1510 to 1570 ohms Main switch pushed off 1 Mohms or higher Main switch pushed on Below 2.5 ohms NG --> See step 8 OK: Go to next step
3. INSPECT CRUISE CONTROL SWITCH WIRE Remove the cruise control switch wire. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition z36-3 - 3 Always Below 1 ohms z36-4 - 1 NG --> REPLACE CRUISE CONTROL SWITCH WIRE OK: Go to next step
4. INSPECT SPIRAL CABLE Check the spiral cable and connector for scratches, cracks, dents and chips. If any defects are found, replace the spiral cable with a new one. Check the spiral cable. Set the spiral cable to the center position. Refer to «REMOVAL»(ref-385228-S22340046582011021400000) . After setting the spiral cable to the center position, rotate the spiral cable 2.5 times clockwise, and measure the resistance according to the value(s) in the table below. Then rotate the spiral cable 5 times counterclockwise, and measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition z36-3 - E12-1 (CCS) Always Below 1 ohms z36-4 - E12-2 (ECC) After setting the spiral cable to the center position, rotate the spiral cable 2.5 times clockwise. Then while rotating the spiral cable 5 times counterclockwise, measure the resistance according to the value(s) in the table below. NOTE: As the spiral cable may break, do not rotate the spiral cable more than the specified amount. Standard Resistance Tester Connection Condition Specified Condition z36-3 - E12-1 (CCS) Always Below 1 ohms z36-4 - E12-2 (ECC) NG --> See step 9 OK: Go to next step
5. CHECK HARNESS AND CONNECTOR (SPIRAL CABLE - ECM AND BODY GROUND) Disconnect the E12 spiral cable connector. Disconnect the A38 ECM connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition E12-1 (CCS) - A38-45 (CCS) Always Below 1 ohms E12-1 (CCS) - Body ground Always 10 kohms or higher E12-2 (ECC) - Body ground Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 6
6. REPLACE ECM. Refer to «REMOVAL»(ref-385180-S10778133792011021400000)
7. PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-385221-S04987457282011021400000)
8. REPLACE CRUISE CONTROL MAIN SWITCH. Refer to «REMOVAL»(ref-385227-S07773173762011021400000)
9. REPLACE SPIRAL CABLE. Refer to «REMOVAL»(ref-385228-S22340046582011021400000)

1. The ECM detects a cruise control switch signal and sends it to the combination meter via the CAN communication line. Then the CRUISE main indicator light comes on.
2. The CRUISE main indicator light circuit uses the CAN for communication. If there is a malfunction in this circuit, check for DTCs in the CAN communication system before troubleshooting this circuit.

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Connecting terminals TC and CG of the DLC3 causes the system to enter self-diagnostic mode. If a malfunction is present, DTCs will be output.

HINT

When a particular warning light remains blinking, a ground short in the wiring of terminal TC of the DLC3 or an internal ground short in the relevant ECU is suspected.

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1. CHECK HARNESS AND CONNECTOR (DLC3 - ECM AND BODY GROUND) Disconnect the A38 ECM connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition E22-13 (TC) - A38-16 (TC) Always Below 1 ohms E22-4 (CG) - Body ground E22-13 (TC) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 2
2. PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-385221-S04987457282011021400000)