System Operation Check

WARNING: This page is about a different car, the 2003 Lexus RX 300 and 2002 Lexus RX 300. However, it is still accessible from the selected car via links, so may be relevant.

Trouble shooting of a instrument panel system complaint begins with verification of the customer problem. If problem occurs, go to step 3. If problem does not occur, go to next step.
If problem does not occur, review conditions under which problem occurred for customer and try to duplicate those conditions. For example, if the problem occurs on rainy days or during high humidity conditions, sprinkle water onto vehicle and see if malfunction occurs. DO NOT sprinkle water directly into engine compartment or onto electronic components. Visually inspect for signs of mechanical and electrical damage. Inspect for blown fuses and damaged relays. Inspect for loose or corroded connections, damaged wiring harnesses and/or switches. Check for a broken or partially broken wire inside insulation, which could cause system malfunction but prove good in a continuity/voltage check with system disconnected. Ensure any aftermarket electronic equipment is properly installed. If fault is found, repair as necessary. If problem still cannot be created, go to next step.
Inspect the multiplex communication system and confirm that there is no trouble by the basic inspection and DTC check. See PRE-CHECK under SELF-DIAGNOSTIC under MULTIPLEX COMMUNICATION SYSTEM article under COMMUNICATION DEVICES in ACCESSORIES & EQUIPMENT.

Determine problem symptom. See PROBLEM SYMPTOM INDEX (COMBINATION METER & GAUGE) table and PROBLEM SYMPTOM INDEX (INDICATOR LIGHT & WARNING LIGHT) table.

PROBLEM SYMPTOM INDEX (COMBINATION METER & GAUGE)

Symptom

Suspected Area ⁽¹⁾

Combination Meter

SRS Warning Light Does Not Light Up

⁽²⁾⁽³⁾⁽⁴⁾⁽⁵⁾⁽⁶⁾

Hi-Beam Indicator Light Does Not Light Up

⁽³⁾⁽⁴⁾⁽⁵⁾⁽⁷⁾

Turn Indicator Light Does Not Light Up

⁽³⁾⁽⁴⁾⁽⁵⁾⁽⁸⁾

ABS Or TRAC Warning Light Does Not Light Up

⁽⁹⁾⁽³⁾⁽⁴⁾⁽⁵⁾⁽¹⁰⁾

AIRSUS Warning Light Does Not Light Up

⁽³⁾⁽⁴⁾⁽⁵⁾⁽¹¹⁾

Malfunction Indicator Light Does Not Light Up

⁽³⁾⁽⁴⁾⁽⁵⁾⁽¹²⁾

Fuel Level Warning Light Does Not Light Up

⁽³⁾⁽¹³⁾⁽⁴⁾⁽⁵⁾

Gauge

Speedometer Does Not Operate Or Abnormal Operation

⁽¹⁴⁾⁽¹⁰⁾

Tachometer Does Not Operate Or Abnormal Operation

⁽¹⁵⁾⁽¹⁶⁾

Fuel Gauge Does Not Operate Or Abnormal Operation

⁽¹⁷⁾⁽⁵⁾⁽⁴⁾

Engine Coolant Temperature Gauge Does Not Operate

⁽¹⁸⁾⁽⁵⁾⁽⁴⁾

⁽¹⁾	Perform test procedures in order listed under suspected area.

⁽²⁾	Check the HEATER fuse in the instrument panel junction block.

⁽³⁾	Check the bulb.

⁽⁴⁾	Check the meter circuit plate. See COMBINATION METER CIRCUIT PLATE under CIRCUIT TESTS.

⁽⁵⁾	Check the wiring harness.

⁽⁶⁾	Check the air bag sensor assembly. See AIR BAG RESTRAINT SYSTEMS article.

⁽⁷⁾	Check the headlight system. See AUTOMATIC HEADLIGHTS & LIGHTING article under HEADLIGHTS in ACCESSORIES & EQUIPMENT.

⁽⁸⁾	Check the turn signal and hazard warning system. See STEERING COLUMN SWITCHES article in ACCESSORIES & EQUIPMENT.

⁽⁹⁾	Check the GAUGE fuse in the instrument panel junction block.

⁽¹⁰⁾	Check the ABS (& TRAC) ECU. See ANTI-LOCK - RX300 article in BRAKES.

⁽¹¹⁾	Check the suspension ECU connector.

⁽¹²⁾	Check the ECM.

⁽¹³⁾	Check the fuel level warning switch. See COMBINATION METER CIRCUIT PLATE under CIRCUIT TESTS.

⁽¹⁴⁾	Check the speedometer. See SPEEDOMETER CIRCUIT under CIRCUIT TESTS.

⁽¹⁵⁾	Check the tachometer. See TACHOMETER CIRCUIT under CIRCUIT TESTS.

⁽¹⁶⁾	Check the igniter signal circuit. See IGNITER SIGNAL CIRCUIT under CIRCUIT TESTS.

⁽¹⁷⁾	Check the fuel gauge circuit. See FUEL GAUGE CIRCUIT under CIRCUIT TESTS.

⁽¹⁸⁾	Check the engine coolant temperature gauge. See ENGINE COOLANT TEMPERATURE GAUGE CIRCUIT under CIRCUIT TESTS.

PROBLEM SYMPTOM INDEX (INDICATOR LIGHT & WARNING LIGHT)

Problem

Suspected Area ⁽¹⁾

Shift Indicator Lights Does Not Light Up

⁽²⁾⁽³⁾⁽⁴⁾

Open Door Warning Light Does Not Light Up

⁽²⁾⁽⁵⁾

Passenger Or Driver Seat Belt Warning Light Does Not Light Up

⁽²⁾⁽⁶⁾

Low Oil Pressure Warning Light Does Not Light Up

⁽²⁾⁽⁷⁾

Discharge Warning Light Does Not Light Up

⁽²⁾⁽⁸⁾

Brake Warning Light Does Not Light Up

⁽²⁾⁽⁹⁾⁽¹⁰⁾⁽¹¹⁾

Headlight Indicator Light Does Not Light Up (USA)

⁽²⁾⁽¹²⁾⁽¹¹⁾

Taillight Indicator Light Does Not Light Up (Canada)

⁽²⁾⁽¹²⁾⁽¹¹⁾

CRUISE MAIN Indicator Light Does Not Light Up

⁽²⁾⁽¹³⁾⁽¹¹⁾

ECT SNOW Or ECT PWR Indicator Light Does Not Light Up

⁽²⁾⁽¹⁴⁾⁽¹¹⁾

TRAC OFF Indicator Light Does Not Light Up

⁽²⁾⁽¹⁵⁾⁽¹¹⁾

Washer Level Warning Light Does Not Light Up

⁽²⁾⁽¹⁶⁾⁽¹¹⁾

Rear Lights Warning Light Does Not Light Up

⁽²⁾⁽¹⁷⁾⁽¹¹⁾

Engine Oil Level Warning Light Does Not Light Up

⁽²⁾⁽¹⁸⁾⁽¹¹⁾

Any Indicator Lights Do Not Light Up

⁽²⁾⁽¹⁹⁾⁽¹¹⁾

⁽¹⁾	Perform test procedures in order listed under suspected area.

⁽²⁾	Check the bulb circuit. See BULB CIRCUIT under CIRCUIT TESTS.

⁽³⁾	Check the A/T shift indicator light. See COMBINATION METER CIRCUIT PLATE under CIRCUIT TESTS.

⁽⁴⁾	Check the transmission control switch. See DTC P1780: PARK/NEUTRAL POSITION SWITCH CIRCUIT MALFUNCTION (RX 300) under DIAGNOSTIC TESTS under DIAGNOSIS - U140E & U140F article under AUTOMATIC TRANSMISSION in TRANSAXLE/TRANSMISSION.

⁽⁵⁾	Check the door courtesy switch. See AUTOMATIC HEADLIGHTS & LIGHTING article under HEADLIGHTS in ACCESSORIES & EQUIPMENT.

⁽⁶⁾	Check the appropriate seat belt buckle switch (driver or passenger). See SEAT BELT BUCKLE SWITCH under COMPONENT TESTS.

⁽⁷⁾	Check the low oil pressure warning switch. See LOW OIL PRESSURE SWITCH under COMPONENT TESTS.

⁽⁸⁾	Check the generator. See appropriate GENERATORS & REGULATORS article under CHARGING SYSTEM in ELECTRICAL.

⁽⁹⁾	Check the parking brake switch. See PARKING BRAKE SWITCH under COMPONENT TESTS.

⁽¹⁰⁾	Check the brake fluid level warning switch. See BRAKE FLUID LEVEL WARNING SWITCH under COMPONENT TESTS.

⁽¹¹⁾	Check the combination meter.

⁽¹²⁾	Check the headlight and taillight system. See AUTOMATIC HEADLIGHTS & LIGHTING article under HEADLIGHTS in ACCESSORIES & EQUIPMENT.

⁽¹³⁾	Check the cruise control switch. See CRUISE CONTROL article in ACCESSORIES & EQUIPMENT.

⁽¹⁴⁾	Check the ECT pattern indicator signal.

⁽¹⁵⁾	Check the ABS & BA & TRAC & VSC ECU. See ANTI-LOCK - RX300 article in BRAKES.

⁽¹⁶⁾	Check the window washer level warning switch. See WINDOW WASHER LEVEL WARNING SWITCH under COMPONENT TESTS.

⁽¹⁷⁾	Check the light failure relay. See LIGHT FAILURE RELAY CIRCUIT under CIRCUIT TESTS.

⁽¹⁸⁾	Check the engine oil level warning sensor. See COMBINATION METER CIRCUIT PLATE under CIRCUIT TESTS.

⁽¹⁹⁾	Check the combination meter ECU power source circuit. See COMBINATION METER ECU POWER SOURCE CIRCUIT under CIRCUIT TESTS.

Inspect the instrument panel system circuits. See CIRCUIT TESTS .
After repairs have been completed, confirm that problem has been eliminated. Operate system under same conditions recorded for original complaint. If problem is no longer present and no DTCs are present, repair has corrected problem. If problem is still present or DTCs are reset, further diagnosis and repair is required.