Cruise Control (Diagnostic Codes & Circuit Tests): Overview Lexus HS I

DESCRIPTION

The wheel speed sensors monitor the wheel rotation speed and send signals to the skid control ECU. The skid control ECU converts the wheel speed signal into a 4-pulse signal and transmits it to the hybrid vehicle control ECU via the combination meter assembly. The hybrid vehicle control ECU determines the vehicle speed based on the frequency of the pulse signal.

HINT

1. A voltage of 12 V or 5 V is output from each ECU and then input to the combination meter assembly. The signal is changed to a pulse signal at the transistor in the combination meter assembly. Each ECU controls the respective system based on the pulse signal.
2. If a short occurs in any of the ECUs or in the wire harness connected to an ECU, all systems in the wiring diagram below will not operate normally.

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1. CHECK DTC OUTPUT (ELECTRONICALLY CONTROLLED BRAKE SYSTEM) Check for DTC (electronically controlled brake system). Refer to «DTC CHECK / CLEAR»(ref-398097-S18517405762011051600000) . OK Electronically controlled brake system is not output. NG --> See step 6 OK: Go to next step
2. CHECK COMBINATION METER ASSEMBLY (SPD SIGNAL WAVEFORM) Inspect the combination meter assembly using an oscilloscope. Turn the power switch on (IG). Measure the voltage between the terminal of the combination meter assembly and the body ground while the wheel is being turned slowly. Standard Voltage Tester Connection Switch Condition Specified Condition F4-40 (+S) - Body ground Power switch on (IG) Voltage generated intermittently TEXT IN ILLUSTRATION *1 Rear view of wire harness connector (to Combination Meter Assembly) HINT: The output voltage should fluctuate up and down, similarly to the diagram, while the wheel is being turned slowly. NG --> See step 5 OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (COMBINATION METER ASSEMBLY - HYBRID VEHICLE CONTROL ECU) Disconnect the combination meter assembly connector. Disconnect the hybrid vehicle control ECU connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition F4-40 (+S) - A58-21 (SPDI) Always Below 1 ohms Reconnect the combination meter assembly connector. Reconnect the hybrid vehicle control ECU connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR (COMBINATION METER ASSEMBLY - HYBRID VEHICLE CONTROL ECU) OK --> See step 4
4. REPLACE HYBRID VEHICLE CONTROL ECU. Refer to «REMOVAL»(ref-398232-S36824664312011051600000)
5. GO TO METER / GAUGE SYSTEM (SPEED SIGNAL CIRCUIT). Refer to «HOW TO PROCEED WITH TROUBLESHOOTING»(ref-398239-S21159643442011051600000)
6. GO TO ELECTRONICALLY CONTROLLED BRAKE SYSTEM. Refer to «DIAGNOSTIC TROUBLE CODE CHART»(ref-398097-S01025085302011051600000)

When the brake pedal is depressed, the stop light switch assembly sends a signal to the hybrid vehicle control ECU. When the hybrid vehicle control ECU 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. Cruise control cancellation occurs when voltage is applied to terminal STP. When the brake is applied, voltage is normally applied to terminal STP of the hybrid vehicle control ECU through the STOP fuse and the stop light switch assembly, and the hybrid vehicle control ECU turns the cruise control off.

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This DTC indicates the internal abnormalities of the hybrid vehicle control ECU.

HINT

The hybrid vehicle control ECU receives signals from each sensor to control all functions of the cruise control system. When a trouble code is detected, the fail-safe function activates and remains on until the power switch is turned off.

The cruise control main switch operates 7 functions: SET, -, TAP-DOWN, RES, +, TAP-UP, and CANCEL. The SET, TAP-DOWN, and - functions, and the RES, TAP-UP, and + functions are operated with the same switch. The cruise control main switch is an automatic return type switch which turns on only while it is being operated it in the direction of each arrow and turns off after being released. The internal contact point of the cruise control main switch is turned on with the switch operation. Then the hybrid vehicle control ECU reads the voltage value that has been changed by the switch operation to control SET, -, RES, +, and CANCEL.

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1. READ VALUE USING TECHSTREAM Connect the Techstream to the DLC3. Turn the power switch on (IG). Turn the Techstream on. Enter the following menus: Powertrain / Cruise Control / Data List. Check the Data List for proper functioning of the cruise control main switch. CRUISE CONTROL Techstream Display Measurement Item/Range Normal Condition Diagnostic Note Main SW M-CPU Cruise control switch (Main CPU)/ON or OFF ON: Cruise main switch (ON-OFF button) on OFF: Cruise main switch (ON-OFF button) 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 - TEXT IN ILLUSTRATION *1 ON/OFF *2 - SET *3 + RES *4 CANCEL OK When the cruise control main switch is operated, the display changes as shown above. RESULT Result Proceed to OK A NG (All items are defective) B NG (1 to 3 items are defective) C C --> See step 8 B --> See step 2 A --> See step 7
2. INSPECT CRUISE CONTROL MAIN SWITCH Remove the cruise control main switch. Refer to «REMOVAL»(ref-398095-S19808404572011051600000) . Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Switch Condition Specified Condition 1 - 3 Main switch off*1 1 Mohms or higher Main switch on Below 2.5 ohms + RES 235 to 245 ohms - SET 617 to 643 ohms CANCEL 1509 to 1571 ohms *1: The cruise control main switch lever is in the neutral position. TEXT IN ILLUSTRATION *1 Component without harness connected (Cruise Control Main Switch) *2 Main Switch (ON-OFF Button) *3 Lever *4 ON-OFF *5 - SET *6 + RES *7 CANCEL - - Install the cruise control main switch. Refer to «INSTALLATION»(ref-398095-S09368009362011051600000) . NG --> See step 8 OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (CRUISE CONTROL MAIN SWITCH - SPIRAL CABLE SUB-ASSEMBLY) Disconnect the connector from the spiral with sensor cable sub-assembly. Disconnect the connector from the cruise control main switch. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition Cruise control main switch side connector terminal 3 - z34-3 Always Below 1 ohms Cruise control main switch side connector terminal 1 - z34-4 Always Below 1 ohms Reconnect the connector to the cruise control main switch. Reconnect the connector to the spiral with sensor cable sub-assembly. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR (CRUISE CONTROL MAIN SWITCH - SPIRAL CABLE SUB-ASSEMBLY) OK: Go to next step
4. CHECK SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY NOTE: The spiral with sensor cable sub-assembly is an important part of the SRS airbag system. Incorrect removal or installation of the spiral with sensor cable sub-assembly may cause airbag deployment. Be sure to read the information shown in the brackets. Remove the spiral with sensor cable sub-assembly. Refer to «REMOVAL»(ref-398090-S07058672812011051600000) . Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition z34-3 - F19-1 (CCS) The spiral with sensor cable sub-assembly is centered Below 1 ohms The spiral with sensor cable sub-assembly position is 2.5 rotations to the left The spiral with sensor cable sub-assembly position is 2.5 rotations to the right z34-4 - F19-2 (ECC) The spiral with sensor cable sub-assembly is centered Below 1 ohms The spiral with sensor cable sub-assembly position is 2.5 rotations to the left The spiral with sensor cable sub-assembly position is 2.5 rotations to the right HINT: The spiral with sensor cable sub-assembly makes a maximum of approximately 5 rotations. Reinstall the spiral with sensor cable sub-assembly. Refer to «INSTALLATION»(ref-398090-S09011507602011051600000) . NG --> See step 9 OK: Go to next step
5. CHECK HARNESS AND CONNECTOR (SPIRAL CABLE SUB-ASSEMBLY - HYBRID VEHICLE CONTROL ECU) Disconnect the hybrid vehicle control ECU connector. Disconnect the spiral with sensor cable sub-assembly connector. Measure the resistance according to the value(s) in the table below. Standard Resistance (Check for Open) Tester Connection Condition Specified Condition F19-1 (CCS) - A58-74 (CCS) Always Below 1 ohms Standard Resistance (Check for Short) Tester Connection Condition Specified Condition F19-1 (CCS) or A58-74 (CCS) - Body ground Always 10 kohms or higher Reconnect the spiral with sensor cable sub-assembly connector. Reconnect the hybrid vehicle control ECU connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR (SPIRAL CABLE SUB-ASSEMBLY - HYBRID VEHICLE CONTROL ECU) OK: Go to next step
6. CHECK HARNESS AND CONNECTOR (SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY - BODY GROUND) Disconnect the spiral with sensor cable sub-assembly connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition F19-2 (ECC) - Body ground Always Below 1 ohms Reconnect the spiral with sensor cable sub-assembly connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR (SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY - BODY GROUND) OK --> See step 10
7. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-398264-S13665175092011051600000)
8. REPLACE CRUISE CONTROL MAIN SWITCH. Refer to «REMOVAL»(ref-398095-S19808404572011051600000)
9. REPLACE SPIRAL WITH SENSOR CABLE SUB-ASSEMBLY. Refer to «REMOVAL»(ref-398090-S07058672812011051600000)
10. REPLACE HYBRID VEHICLE CONTROL ECU. Refer to «REMOVAL»(ref-398232-S36824664312011051600000)

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

Connecting terminals TC and CG of the DLC3 causes the system to enter self-diagnostic mode. If a malfunction is present, the cruise main indicator light will blink.

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 (TERMINAL TC of DLC3 - HYBRID VEHICLE CONTROL ECU) Disconnect the hybrid vehicle control ECU connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A58-33 (TC) - F11-13 (TC) Always Below 1 ohms Connect the hybrid vehicle control ECU connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR (DLC3 - HYBRID VEHICLE CONTROL ECU) OK: Go to next step
2. CHECK HARNESS AND CONNECTOR (TERMINAL CG of DLC3 - BODY GROUND) Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition F11-4 (CG) - Body ground Always Below 1 ohms TEXT IN ILLUSTRATION *1 DLC3 NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR (DLC3 - BODY GROUND) OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (TERMINAL TC of DLC3 - BODY GROUND) Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition F11-13 (TC) - Body ground Always 10 kohms or higher TEXT IN ILLUSTRATION *1 DLC3 NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OR EACH ECU OK --> See step 4
4. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-398264-S13665175092011051600000)