Audio / Video System (W/ Navigation) (Diagnostic Codes & Symptom Tests): Overview Lexus CT I

DESCRIPTION

This DTC is stored when a malfunction occurs in a connected device.

These DTCs are stored when a malfunction occurs in the radio receiver assembly.

This DTC is stored when a malfunction occurs in the stereo component amplifier assembly.

This DTC is stored when a malfunction occurs in the radio receiver assembly.

This DTC is stored when a malfunction occurs in the multi-media interface ECU assembly.

Scheme 145

This DTC is stored when a communication error occurs with a USB device or "iPod".

This DTC is stored when the disc in the radio receiver assembly cannot read the media.

These DTCs are stored when a malfunction occurs in the satellite radio antenna which is connected to the radio receiver assembly.

Power is supplied to the radio receiver assembly illumination when the light control switch is in the tail or head position.

Scheme 146

If there is a short in a speaker circuit, the stereo component amplifier assembly detects the short and stops output to the speakers.

Thus sound cannot be heard from the speakers even if there is no malfunction in the stereo component amplifier assembly, DCM (telematics transceiver)*1 or speakers.

1. *1: w/ Manual (SOS) Switch

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Scheme 149

1. for 10 Speakers
2. for 13 Speakers

Scheme 150

Scheme 151

Scheme 152

Scheme 153

Scheme 154

Scheme 155

Scheme 156

Scheme 157

1. CONFIRM MODEL Choose the model to be inspected. Result Model Proceed to for 10 Speakers A for 13 Speakers B B --> See step 3 A: Go to next step
2. CHECK HARNESS AND CONNECTOR Disconnect the connectors from the stereo component amplifier assembly, DCM (telematics transceiver)*1 and speakers. *1: w/ Manual (SOS) Switch Measure the resistance between the front No. 1 speaker assembly RH and the stereo component amplifier assembly to check for an open circuit in the wire harness. Standard Resistance Tester Connection Condition Specified Condition H57-10 (FR+) - J1-1 Always Below 1 ohms H57-9 (FR-) - J1-2 Always Below 1 ohms Measure the resistance between the front No. 1 speaker assembly LH and the stereo component amplifier assembly to check for an open circuit in the wire harness. Standard Resistance Tester Connection Condition Specified Condition H57-3 (FL+) - K1-1 Always Below 1 ohms H57-8 (FL-) - K1-2 Always Below 1 ohms w/o Manual (SOS) Switch: Measure the resistance between the front No. 2 speaker assembly RH and the stereo component amplifier assembly to check for an open circuit in the wire harness. Standard Resistance Tester Connection Condition Specified Condition H58-4 (MR+) - I3-2 Always Below 1 ohms H58-10 (MR-) - I3-1 Always Below 1 ohms w/ Manual (SOS) Switch: Measure the resistance between the stereo component amplifier assembly and the DCM (telematics transceiver) to check for an open circuit in the wire harness. Standard Resistance Tester Connection Condition Specified Condition H58-4 (MR+) - H67-2 (SPI+) Always Below 1 ohms H58-10 (MR-) - H67-3 (SPI-) Always Below 1 ohms w/ Manual (SOS) Switch: Measure the resistance between the front No. 2 speaker assembly RH and the DCM (telematics transceiver) to check for an open circuit in the wire harness. Standard Resistance Tester Connection Condition Specified Condition H67-5 (SPO+) - I3-2 Always Below 1 ohms H67-6 (SPO-) - I3-1 Always Below 1 ohms Measure the resistance between the front No. 2 speaker assembly LH and the stereo component amplifier assembly to check for an open circuit in the wire harness. Standard Resistance Tester Connection Condition Specified Condition H58-3 (ML+) - I5-2 Always Below 1 ohms H58-9 (ML-) - I5-1 Always Below 1 ohms w/o Manual (SOS) Switch: Measure the resistance between the front No. 3 speaker assembly RH and the stereo component amplifier assembly to check for an open circuit in the wire harness. Standard Resistance Tester Connection Condition Specified Condition H58-4 (MR+) - I4-2 Always Below 1 ohms H58-10 (MR-) - I4-1 Always Below 1 ohms w/ Manual (SOS) Switch: Measure the resistance between the front No. 3 speaker assembly RH and the DCM (telematics transceiver) to check for an open circuit in the wire harness. Standard Resistance Tester Connection Condition Specified Condition H67-5 (SPO+) - I4-2 Always Below 1 ohms H67-6 (SPO-) - I4-1 Always Below 1 ohms Measure the resistance between the front No. 3 speaker assembly LH and the stereo component amplifier assembly to check for an open circuit in the wire harness. Standard Resistance Tester Connection Condition Specified Condition H58-3 (ML+) - I6-2 Always Below 1 ohms H58-9 (ML-) - I6-1 Always Below 1 ohms Measure the resistance between the front No. 4 speaker assembly and the stereo component amplifier assembly to check for an open circuit in the wire harness. Standard Resistance Tester Connection Condition Specified Condition H58-8 (CTR+) - I2-2 (+) Always Below 1 ohms H58-7 (CTR-) - I2-1 (-) Always Below 1 ohms Measure the resistance between the rear speaker assembly RH and the stereo component amplifier assembly to check for an open circuit in the wire harness. Standard Resistance Tester Connection Condition Specified Condition H57-5 (RR+) - L4-1 Always Below 1 ohms H57-12 (RR-) - L4-2 Always Below 1 ohms Measure the resistance between the rear speaker assembly LH and the stereo component amplifier assembly to check for an open circuit in the wire harness. Standard Resistance Tester Connection Condition Specified Condition H57-4 (RL+) - M4-1 Always Below 1 ohms H57-11 (RL-) - M4-2 Always Below 1 ohms Measure the resistance between the No. 1 speaker assembly with box and the stereo component amplifier assembly to check for an open circuit in the wire harness. Standard Resistance Tester Connection Condition Specified Condition H58-1 (WF1+) - P15-2 (WF1+) Always Below 1 ohms H58-2 (WF2+) - P15-4 (WF2+) Always Below 1 ohms Measure the resistance between the stereo component amplifier assembly and body ground to check for a short circuit in the wire harness. Standard Resistance Tester Connection Condition Specified Condition H57-10 (FR+) - Body ground Always 10 kohms or higher H57-9 (FR-) - Body ground Always 10 kohms or higher H57-3 (FL+) - Body ground Always 10 kohms or higher H57-8 (FL-) - Body ground Always 10 kohms or higher H57-5 (RR+) - Body ground Always 10 kohms or higher H57-12 (RR-) - Body ground Always 10 kohms or higher H57-4 (RL+) - Body ground Always 10 kohms or higher H57-11 (RL-) - Body ground Always 10 kohms or higher H58-4 (MR+) - Body ground Always 10 kohms or higher H58-10 (MR-) - Body ground Always 10 kohms or higher H58-3 (ML+) - Body ground Always 10 kohms or higher H58-9 (ML-) - Body ground Always 10 kohms or higher H58-8 (CTR+) - Body ground Always 10 kohms or higher H58-7 (CTR-) - Body ground Always 10 kohms or higher H58-1 (WF1+) - Body ground Always 10 kohms or higher H58-2 (WF2+) - Body ground Always 10 kohms or higher w/ Manual (SOS) Switch: Measure the resistance between the DCM (telematics transceiver) and body ground to check for a short circuit in the wire harness. Standard Resistance Tester Connection Condition Specified Condition H67-5 (SPO+) - Body ground Always 10 kohms or higher H67-6 (SPO-) - Body ground Always 10 kohms or higher Proceed to the next step based on the inspection result. Result Condition Proceed to NG A OK B B --> See step 4 A --> REPAIR OR REPLACE HARNESS OR CONNECTOR
3. CHECK HARNESS AND CONNECTOR Disconnect the connectors from the stereo component amplifier assembly, DCM (telematics transceiver)*1 and speakers. *1: w/ Manual (SOS) Switch Measure the resistance between the front No. 1 speaker assembly RH and the stereo component amplifier assembly to check for an open circuit in the wire harness. Standard Resistance Tester Connection Condition Specified Condition H57-10 (FR+) - J1-1 Always Below 1 ohms H57-9 (FR-) - J1-2 Always Below 1 ohms Measure the resistance between the front No. 1 speaker assembly LH and the stereo component amplifier assembly to check for an open circuit in the wire harness. Standard Resistance Tester Connection Condition Specified Condition H57-3 (FL+) - K1-1 Always Below 1 ohms H57-8 (FL-) - K1-2 Always Below 1 ohms w/o Manual (SOS) Switch: Measure the resistance between the front No. 2 speaker assembly RH and the stereo component amplifier assembly to check for an open circuit in the wire harness. Standard Resistance Tester Connection Condition Specified Condition H58-4 (MR+) - I3-2 Always Below 1 ohms H58-10 (MR-) - I3-1 Always Below 1 ohms w/ Manual (SOS) Switch: Measure the resistance between the stereo component amplifier assembly and the DCM (telematics transceiver) to check for an open circuit in the wire harness. Standard Resistance Tester Connection Condition Specified Condition H58-4 (MR+) - H67-2 (SPI+) Always Below 1 ohms H58-10 (MR-) - H67-3 (SPI-) Always Below 1 ohms w/ Manual (SOS) Switch: Measure the resistance between the front No. 2 speaker assembly RH and the DCM (telematics transceiver) to check for an open circuit in the wire harness. Standard Resistance Tester Connection Condition Specified Condition H67-5 (SPO+) - I3-2 Always Below 1 ohms H67-6 (SPO-) - I3-1 Always Below 1 ohms Measure the resistance between the front No. 2 speaker assembly LH and the stereo component amplifier assembly to check for an open circuit in the wire harness. Standard Resistance Tester Connection Condition Specified Condition H58-3 (ML+) - I5-2 Always Below 1 ohms H58-9 (ML-) - I5-1 Always Below 1 ohms w/o Manual (SOS) Switch: Measure the resistance between the front No. 3 speaker assembly RH and the stereo component amplifier assembly to check for an open circuit in the wire harness. Standard Resistance Tester Connection Condition Specified Condition H58-4 (MR+) - I4-2 Always Below 1 ohms H58-10 (MR-) - I4-1 Always Below 1 ohms w/ Manual (SOS) Switch: Measure the resistance between the front No. 3 speaker assembly RH and the DCM (telematics transceiver) to check for an open circuit in the wire harness. Standard Resistance Tester Connection Condition Specified Condition H67-5 (SPO+) - I4-2 Always Below 1 ohms H67-6 (SPO-) - I4-1 Always Below 1 ohms Measure the resistance between the front No. 3 speaker assembly LH and the stereo component amplifier assembly to check for an open circuit in the wire harness. Standard Resistance Tester Connection Condition Specified Condition H58-3 (ML+) - I6-2 Always Below 1 ohms H58-9 (ML-) - I6-1 Always Below 1 ohms Measure the resistance between the front No. 4 speaker assembly and the stereo component amplifier assembly to check for an open circuit in the wire harness. Standard Resistance Tester Connection Condition Specified Condition H58-8 (CTR+) - I2-2 (+) Always Below 1 ohms H58-7 (CTR-) - I2-1 (-) Always Below 1 ohms Measure the resistance between the rear No. 2 speaker assembly RH and the stereo component amplifier assembly to check for an open circuit in the wire harness. Standard Resistance Tester Connection Condition Specified Condition H57-5 (RR+) - Q10-2 (+) Always Below 1 ohms H57-12 (RR-) - Q10-1 (-) Always Below 1 ohms Measure the resistance between the rear No. 2 speaker assembly LH and the stereo component amplifier assembly to check for an open circuit in the wire harness. Standard Resistance Tester Connection Condition Specified Condition H57-4 (RL+) - P14-2 (+) Always Below 1 ohms H57-11 (RL-) - P14-1 (-) Always Below 1 ohms Measure the resistance between the No. 1 speaker assembly with box and the stereo component amplifier assembly to check for an open circuit in the wire harness. Standard Resistance Tester Connection Condition Specified Condition H58-1 (WF1+) - P15-2 (WF1+) Always Below 1 ohms H58-2 (WF2+) - P15-4 (WF2+) Always Below 1 ohms Measure the resistance between the stereo component amplifier assembly and body ground to check for a short circuit in the wire harness. Standard Resistance Tester Connection Condition Specified Condition H57-10 (FR+) - Body ground Always 10 kohms or higher H57-9 (FR-) - Body ground Always 10 kohms or higher H57-3 (FL+) - Body ground Always 10 kohms or higher H57-8 (FL-) - Body ground Always 10 kohms or higher H57-5 (RR+) - Body ground Always 10 kohms or higher H57-12 (RR-) - Body ground Always 10 kohms or higher H57-4 (RL+) - Body ground Always 10 kohms or higher H57-11 (RL-) - Body ground Always 10 kohms or higher H58-4 (MR+) - Body ground Always 10 kohms or higher H58-10 (MR-) - Body ground Always 10 kohms or higher H58-3 (ML+) - Body ground Always 10 kohms or higher H58-9 (ML-) - Body ground Always 10 kohms or higher H58-8 (CTR+) - Body ground Always 10 kohms or higher H58-7 (CTR-) - Body ground Always 10 kohms or higher H58-1 (WF1+) - Body ground Always 10 kohms or higher H58-2 (WF2+) - Body ground Always 10 kohms or higher w/ Manual (SOS) Switch: Measure the resistance between the DCM (telematics transceiver) and body ground to check for a short circuit in the wire harness. Standard Resistance Tester Connection Condition Specified Condition H67-5 (SPO+) - Body ground Always 10 kohms or higher H67-6 (SPO-) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
4. INSPECT FRONT NO. 1 SPEAKER ASSEMBLY Resistance check Measure the resistance according to the value(s) in the table below. Standard Resistance FOR 10 SPEAKERS Tester Connection Condition Specified Condition J1-1 - J1-2 Always 3.2 to 4.8 ohms K1-1 - K1-2 Always 3.2 to 4.8 ohms FOR 13 SPEAKERS Tester Connection Condition Specified Condition J1-1 - J1-2 Always 5 to 7 ohms K1-1 - K1-2 Always 5 to 7 ohms TEXT IN ILLUSTRATION *a Component without harness connected (Front No. 1 Speaker Assembly) NG --> See step 14 OK: Go to next step
5. INSPECT FRONT NO. 2 SPEAKER ASSEMBLY Resistance check Measure the resistance according to the value(s) in the table below. Standard Resistance FOR 10 SPEAKERS Tester Connection Condition Specified Condition I3-2 - I3-1 Always 3.2 to 4.8 ohms I5-2 - I5-1 Always 3.2 to 4.8 ohms FOR 13 SPEAKERS Tester Connection Condition Specified Condition I3-2 - I3-1 Always 4.6 to 7 ohms I5-2 - I5-1 Always 4.6 to 7 ohms TEXT IN ILLUSTRATION *a Component without harness connected (Front No. 2 Speaker Assembly) NG --> See step 20 OK: Go to next step
6. INSPECT FRONT NO. 3 SPEAKER ASSEMBLY Resistance check Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition I4-2 - I4-1 Always 10 kohms or higher I6-2 - I6-1 Always 10 kohms or higher TEXT IN ILLUSTRATION *a Component without harness connected (Front No. 3 Speaker Assembly) NG --> See step 19 OK: Go to next step
7. REPLACE FRONT NO. 3 SPEAKER ASSEMBLY Check that the malfunction disappears when a known good speaker is installed. Refer to «REMOVAL»(ref-568798-S25708132802013072300000) . OK Malfunction disappears. HINT: Connect all the connectors to the front No. 3 speaker assemblies that were disconnected. When there is a possibility that either the right or left speaker is defective, inspect by interchanging the right one with the left one. Perform the above inspection on both LH and RH sides. NG --> See step 8 OK --> END (FRONT NO. 3 SPEAKER ASSEMBLY WAS DEFECTIVE)
8. INSPECT FRONT NO. 4 SPEAKER ASSEMBLY Resistance check Measure the resistance according to the value(s) in the table below. Standard Resistance FOR 10 SPEAKERS Tester Connection Condition Specified Condition I2-1 (-) - I2-2 (+) Always 3.2 to 4.8 ohms FOR 13 SPEAKERS Tester Connection Condition Specified Condition I2-1 (-) - I2-2 (+) Always 4.6 to 7 ohms TEXT IN ILLUSTRATION *a Component without harness connected (Front No. 4 Speaker Assembly) NG --> See step 16 OK: Go to next step
9. CONFIRM MODEL Choose the model to be inspected. Result Model Proceed to for 10 Speakers A for 13 Speakers B B --> See step 11 A: Go to next step
10. INSPECT REAR SPEAKER ASSEMBLY Resistance check Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition L4-1 - L4-2 Always 3.2 to 4.8 ohms M4-1 - M4-2 Always 3.2 to 4.8 ohms TEXT IN ILLUSTRATION *a Component without harness connected (Rear Speaker Assembly) Proceed to the next step based on the inspection result. Result Condition Proceed to NG A OK B B --> See step 12 A --> See step 15
11. INSPECT REAR NO. 2 SPEAKER ASSEMBLY Resistance check Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition Q10-1 (-) - Q10-2 (+) Always 4.6 to 7 ohms P14-1 (-) - P14-2 (+) Always 4.6 to 7 ohms TEXT IN ILLUSTRATION *a Component without harness connected (Rear No. 2 Speaker Assembly) NG --> See step 22 OK: Go to next step
12. INSPECT NO. 1 SPEAKER ASSEMBLY WITH BOX Resistance check Measure the resistance according to the value(s) in the table below. Standard Resistance FOR 10 SPEAKERS Tester Connection Condition Specified Condition P15-2 (WF1+) - P15-4 (WF2+) Always 1.6 to 2.4 ohms FOR 13 SPEAKERS Tester Connection Condition Specified Condition P15-2 (WF1+) - P15-4 (WF2+) Always 11.6 to 12.4 ohms TEXT IN ILLUSTRATION *a Component without harness connected (No. 1 Speaker Assembly with Box) Proceed to the next step based on the inspection result. Result Condition Proceed to OK (w/ Manual (SOS) Switch) A OK (w/o Manual (SOS) Switch) B NG C B --> See step 17 C --> See step 21 A: Go to next step
13. INSPECT DCM (TELEMATICS TRANSCEIVER) Resistance check Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition H67-2 (SPI+) - H67-5 (SPO+) Always Below 1 ohms H67-3 (SPI-) - H67-6 (SPO-) Always Below 1 ohms H67-2 (SPI+) - H67-3 (SPI-) Always 10 kohms or higher H67-5 (SPO+) - H67-6 (SPO-) Always 10 kohms or higher H67-2 (SPI+) - Body ground Always 10 kohms or higher H67-3 (SPI-) - Body ground Always 10 kohms or higher TEXT IN ILLUSTRATION *a Component without harness connected (DCM (Telematics Transceiver)) NG --> See step 18 OK --> See step 17
14. REPLACE FRONT NO. 1 SPEAKER ASSEMBLY. Refer to «REMOVAL»(ref-568798-S33253903172013072300000)
15. REPLACE REAR SPEAKER ASSEMBLY. Refer to «REMOVAL»(ref-568798-S18158421872013072300000)
16. REPLACE FRONT NO. 4 SPEAKER ASSEMBLY. Refer to «REMOVAL»(ref-568798-S32423900912013072300000)
17. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-568801-S31651890872013072300000)
18. REPLACE DCM (TELEMATICS TRANSCEIVER). Refer to «REMOVAL»(ref-568805-S08474017522013072300000)
19. REPLACE FRONT NO. 3 SPEAKER ASSEMBLY. Refer to «REMOVAL»(ref-568798-S25708132802013072300000)
20. REPLACE FRONT NO. 2 SPEAKER ASSEMBLY. Refer to «REMOVAL»(ref-568798-S32423900912013072300000)
21. REPLACE NO. 1 SPEAKER ASSEMBLY WITH BOX. Refer to «REMOVAL»(ref-568798-S18726661642013072300000)
22. REPLACE REAR NO. 2 SPEAKER ASSEMBLY. Refer to «REMOVAL»(ref-568798-S20633440502013072300000)

The multi-media interface ECU assembly sends the sound signal to the navigation computer sub-assembly*1 or display and navigation module display*2 through this circuit.

If there is an open or short in the circuit, sound cannot be heard from the speakers even if there is no malfunction in the stereo component amplifier assembly, radio receiver assembly, navigation computer sub-assembly*1, display and navigation module display*2, DCM (telematics transceiver)*3 or speakers.

1. *1: w/ Navigation System (for HDD)
2. *2: w/ Navigation System (for DVD)
3. *3: w/ Manual (SOS) Switch

Scheme 158

The No. 1 stereo jack adapter assembly sends the sound signal from an external device to the radio receiver assembly through this circuit.

The sound signal that has been sent is amplified by the stereo component amplifier assembly or radio receiver assembly, and then is sent to the speakers.

If there is an open or short in the circuit, sound cannot be heard from the speakers even if there is no malfunction in the stereo component amplifier assembly, radio receiver assembly, DCM (telematics transceiver)*1 or speakers.

1. *1: w/ Manual (SOS) Switch

Scheme 159

Scheme 160

1. CHECK HARNESS AND CONNECTOR (RADIO RECEIVER ASSEMBLY - NO. 1 STEREO JACK ADAPTER ASSEMBLY) Disconnect the No. 1 stereo jack adapter assembly connector and radio receiver assembly connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition H120-9 (AUXO) - H50-5 (AUXI) Always Below 1 ohms H120-8 (ASGN) - H50-21 (ASGN) Always Below 1 ohms H120-6 (ARO) - H50-19 (ARI) Always Below 1 ohms H120-7 (ALO) - H50-20 (ALI) Always Below 1 ohms H120-10 (AGND) - H50-6 (AGND) Always Below 1 ohms H120-9 (AUXO) - Body ground Always 10 kohms or higher H120-8 (ASGN) - Body ground Always 10 kohms or higher H120-6 (ARO) - Body ground Always 10 kohms or higher H120-7 (ALO) - Body ground Always 10 kohms or higher H120-10 (AGND) - Body ground Always 10 kohms or higher TEXT IN ILLUSTRATION *a Front view of wire harness connector (to Radio Receiver Assembly) *b Front view of wire harness connector (to No. 1 Stereo Jack Adapter Assembly) NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 2
2. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-568801-S31651890872013072300000)

The No. 1 stereo jack adapter assembly sends the sound data from an external device to the multi-media interface ECU assembly through this circuit.

Scheme 161

Scheme 162

1. CHECK HARNESS AND CONNECTOR Disconnect the multi-media interface ECU assembly connector and No. 1 stereo jack adapter assembly connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition H120-3 (UDO+) - H121-2 (UDI+) Always Below 1 ohms H120-2 (UDO-) - H121-3 (UDI-) Always Below 1 ohms H120-5 (UJSS) - H121-5 (UESS) Always Below 1 ohms H120-3 (UDO+) - Body ground Always 10 kohms or higher H120-2 (UDO-) - Body ground Always 10 kohms or higher H120-5 (UJSS) - Body ground Always 10 kohms or higher TEXT IN ILLUSTRATION *a Front view of wire harness connector (to Multi-media Interface ECU Assembly) *b Front view of wire harness connector (to No. 1 Stereo Jack Adapter Assembly) NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 2
2. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-568801-S31651890872013072300000)

The DCM (telematics transceiver) sends a mute signal to the stereo component amplifier assembly.

The stereo component amplifier assembly controls the volume according to the mute signal from the DCM (telematics transceiver).

Scheme 163

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Scheme 165

1. INSPECT DCM (TELEMATICS TRANSCEIVER) Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition H67-17 (MUTE) - Body ground Power switch on (ACC), audio system is playing --> Emergency call mode Above 3.5 V --> Below 1 V TEXT IN ILLUSTRATION *a Component with harness connected (DCM (Telematics Transceiver)) NG --> See step 2 OK --> See step 4
2. CHECK HARNESS AND CONNECTOR Disconnect the stereo component amplifier assembly connector and DCM (telematics transceiver) connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition H56-7 (TMUT) - H67-17 (MUTE) Always Below 1 ohms H56-7 (TMUT) - Body ground Always 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
3. INSPECT STEREO COMPONENT AMPLIFIER ASSEMBLY Reconnect the stereo component amplifier assembly connector. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition H67-17 (MUTE) - Body ground Power switch on (ACC) Above 3.5 V TEXT IN ILLUSTRATION *a Front view of wire harness connector (DCM (Telematics Transceiver)) NG --> See step 5 OK --> See step 6
4. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-568801-S31651890872013072300000)
5. REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY. Refer to «REMOVAL»(ref-568798-S10922327672013072300000)
6. REPLACE DCM (TELEMATICS TRANSCEIVER). Refer to «REMOVAL»(ref-568805-S08474017522013072300000)

This circuit is necessary for the Automatic Sound Levelizer (ASL) built into the stereo component amplifier assembly.

Speed signals are received from the combination meter assembly and used for the ASL.

The ASL function automatically adjusts the radio system volume level in order to compensate for increased vehicle noise (vehicle noise tends to increase as vehicle speed increases). The ASL adjusts the volume level based upon vehicle speed signals that it receives from the combination meter assembly.

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 following diagram will not operate normally.

Scheme 166

Scheme 167

1. INSPECT COMBINATION METER ASSEMBLY (OUTPUT WAVEFORM) Check the output waveform. Remove the combination meter assembly with the connector still connected. Connect an oscilloscope to terminal H19-40 (+S) and body ground. Turn the power switch on (IG). Turn a wheel slowly. Check the signal waveform according to the condition(s) in the table below. Item Condition Measurement terminal H19-40 (+S) - Body ground Tool setting 5 V/DIV., 20 ms./DIV. Vehicle condition Wheel being rotated OK The waveform is similar to that shown in the illustration. HINT: When the system is functioning normally, one wheel revolution generates 4 pulses. As the vehicle speed increases, the width indicated by (A) in the illustration narrows. TEXT IN ILLUSTRATION *a Component with harness connected (Combination Meter Assembly) NG --> See step 5 OK: Go to next step
2. CHECK HARNESS AND CONNECTOR Disconnect the stereo component amplifier assembly and combination meter assembly connectors. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition H56-2 (SPD) - H19-40 (+S) Always Below 1 ohms NG --> See step 3 OK --> See step 4
3. CHECK HARNESS AND CONNECTOR (STEREO COMPONENT AMPLIFIER ASSEMBLY - JUNCTION CONNECTOR) Disconnect the stereo component amplifier assembly connector and junction connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition H56-2 (SPD) - H117-89 Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> REPLACE JUNCTION CONNECTOR
4. REPLACE STEREO COMPONENT AMPLIFIER ASSEMBLY. Refer to «REMOVAL»(ref-568798-S10922327672013072300000)
5. GO TO METER / GAUGE SYSTEM. Refer to «Speed Signal Circuit»(ref-568762-S10347095632013072300000)