2007 Lexus GS 430FACTORY OEM SERVICE PROCEDURE

Problem Symptoms Table

HINT:

Use the table below to help determine the cause of the problem symptom. The potential cases of the symptoms are listed in order of probability in the "Suspected Area" column of the table. Check each symptom by checking the suspected areas in the order they are listed. Replace parts as necessary.

PROBLEM SYMPTOMS CHART

Symptom Suspected Area See
Engine does not crank (does not start) 1. Starter INSPECTION
2. STARTER relay STARTER RELAY
3. Engine Switch INSPECTION
No initial combustion (does not start) 1. ECM power source circuit ECM POWER SOURCE CIRCUIT 
2. VC output circuit VC OUTPUT CIRCUIT 
3. Fuel pump control circuit FUEL PUMP CONTROL CIRCUIT 
4. ECM TERMINALS OF ECM 
Engine cranks normally (difficult to start) 1. Fuel pump control circuit FUEL PUMP CONTROL CIRCUIT 
2. Compression ENGINE
Cold engine (difficult to start) 1. Starter signal circuit DTC P0617 STARTER RELAY CIRCUIT HIGH 
2. Fuel pump control circuit FUEL PUMP CONTROL CIRCUIT 
3. Spark plug ON-VEHICLE INSPECTION
4. Ignition system ON-VEHICLE INSPECTION
5. Injector INSPECTION
Hot engine (difficult to start) 1. Starter signal circuit DTC P0617 STARTER RELAY CIRCUIT HIGH 
2. Fuel pump control circuit FUEL PUMP CONTROL CIRCUIT 
3. Spark plug ON-VEHICLE INSPECTION
4. Ignition system ON-VEHICLE INSPECTION
5. Injector INSPECTION
High engine idle speed 1. A/C signal circuit (compressor circuit) AIR CONDITIONING COMPRESSOR MAGNETIC CLUTCH CIRCUIT
2. ECM power source circuit ECM POWER SOURCE CIRCUIT 
3. Electronic throttle control system DTC P0120 THROTTLE / PEDAL POSITION SENSOR / SWITCH "A" CIRCUIT; DTC P0122 THROTTLE / PEDAL POSITION SENSOR / SWITCH "A" CIRCUIT LOW INPUT; DTC P0123 THROTTLE / PEDAL POSITION SENSOR / SWITCH "A" CIRCUIT HIGH INPUT; DTC P0220 THROTTLE / PEDAL POSITION SENSOR / SWITCH "B" CIRCUIT; DTC P0222 THROTTLE / PEDAL POSITION SENSOR / SWITCH "B" CIRCUIT LOW INPUT; DTC P0223 THROTTLE / PEDAL POSITION SENSOR / SWITCH "B" CIRCUIT HIGH INPUT; DTC P2135 THROTTLE / PEDAL POSITION SENSOR / SWITCH "A" / "B" VOLTAGE CORRELATION 
4. Air induction system IACV CONTROL CIRCUIT 
5. PCV hose ON-VEHICLE INSPECTION
Low engine idle speed 1. A/C signal circuit (compressor circuit) AIR CONDITIONING COMPRESSOR MAGNETIC CLUTCH CIRCUIT
2. Fuel pump control circuit FUEL PUMP CONTROL CIRCUIT 
3. Electronic throttle control system DTC P0120 THROTTLE / PEDAL POSITION SENSOR / SWITCH "A" CIRCUIT; DTC P0122 THROTTLE / PEDAL POSITION SENSOR / SWITCH "A" CIRCUIT LOW INPUT; DTC P0123 THROTTLE / PEDAL POSITION SENSOR / SWITCH "A" CIRCUIT HIGH INPUT; DTC P0220 THROTTLE / PEDAL POSITION SENSOR / SWITCH "B" CIRCUIT; DTC P0222 THROTTLE / PEDAL POSITION SENSOR / SWITCH "B" CIRCUIT LOW INPUT; DTC P0223 THROTTLE / PEDAL POSITION SENSOR / SWITCH "B" CIRCUIT HIGH INPUT; DTC P2135 THROTTLE / PEDAL POSITION SENSOR / SWITCH "A" / "B" VOLTAGE CORRELATION 
4. Air induction system IACV CONTROL CIRCUIT 
5. PCV hose ON-VEHICLE INSPECTION
Rough idling 1. Compression ENGINE
2. Fuel pump control circuit FUEL PUMP CONTROL CIRCUIT 
3. Electronic throttle control system DTC P0120 THROTTLE / PEDAL POSITION SENSOR / SWITCH "A" CIRCUIT; DTC P0122 THROTTLE / PEDAL POSITION SENSOR / SWITCH "A" CIRCUIT LOW INPUT; DTC P0123 THROTTLE / PEDAL POSITION SENSOR / SWITCH "A" CIRCUIT HIGH INPUT; DTC P0220 THROTTLE / PEDAL POSITION SENSOR / SWITCH "B" CIRCUIT; DTC P0222 THROTTLE / PEDAL POSITION SENSOR / SWITCH "B" CIRCUIT LOW INPUT; DTC P0223 THROTTLE / PEDAL POSITION SENSOR / SWITCH "B" CIRCUIT HIGH INPUT; DTC P2135 THROTTLE / PEDAL POSITION SENSOR / SWITCH "A" / "B" VOLTAGE CORRELATION 
4. Air induction system IACV CONTROL CIRCUIT 
5. PCV hose ON-VEHICLE INSPECTION
Hunting (when idling) 1. ECM power source circuit ECM POWER SOURCE CIRCUIT 
2. Fuel pump control circuit FUEL PUMP CONTROL CIRCUIT 
3. Spark plug ON-VEHICLE INSPECTION
4. Ignition system ON-VEHICLE INSPECTION
5. Injector INSPECTION
6. Electronic throttle control system DTC P0120 THROTTLE / PEDAL POSITION SENSOR / SWITCH "A" CIRCUIT; DTC P0122 THROTTLE / PEDAL POSITION SENSOR / SWITCH "A" CIRCUIT LOW INPUT; DTC P0123 THROTTLE / PEDAL POSITION SENSOR / SWITCH "A" CIRCUIT HIGH INPUT; DTC P0220 THROTTLE / PEDAL POSITION SENSOR / SWITCH "B" CIRCUIT; DTC P0222 THROTTLE / PEDAL POSITION SENSOR / SWITCH "B" CIRCUIT LOW INPUT; DTC P0223 THROTTLE / PEDAL POSITION SENSOR / SWITCH "B" CIRCUIT HIGH INPUT; DTC P2135 THROTTLE / PEDAL POSITION SENSOR / SWITCH "A" / "B" VOLTAGE CORRELATION 
7. Air induction system IACV CONTROL CIRCUIT 
8. PCV hose ON-VEHICLE INSPECTION
Hesitation/Poor acceleration (poor driveability) 1. Fuel pump control circuit FUEL PUMP CONTROL CIRCUIT 
2. A/T faulty PROBLEM SYMPTOMS TABLE
3. Spark plug ON-VEHICLE INSPECTION
4. Ignition system ON-VEHICLE INSPECTION
5. Injector INSPECTION
Surging (poor driveability) 1. Fuel pump control circuit FUEL PUMP CONTROL CIRCUIT 
2. Spark plug ON-VEHICLE INSPECTION
3. Ignition system ON-VEHICLE INSPECTION
4. Injector INSPECTION
Engine stalls soon after starting 1. Fuel pump control circuit FUEL PUMP CONTROL CIRCUIT 
2. Spark plug ON-VEHICLE INSPECTION
3. Ignition system ON-VEHICLE INSPECTION
4. Injector INSPECTION
Engine stalls during A/C operation 1. A/C signal circuit (compressor circuit) AIR CONDITIONING COMPRESSOR MAGNETIC CLUTCH CIRCUIT
2. ECM TERMINALS OF ECM 
Unable/difficult to refuel 1. Refueling valve (canister) ON-VEHICLE INSPECTION
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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