Low Idle Speed

• Check Idle Air Control (IAC) valve circuit.
• Check A/C signal circuit.
• Check switch condition signal circuit. See CODE 51 in appropriate article;

For GS300 TESTS W/CODES

For SC300 TESTS W/CODES

For SC400 TESTS W/CODES

• Check Park/Neutral Position (PNP) switch circuit (clutch start switch circuit on SC300 M/T).
• Check fuel pump control circuit. See CODE 78 in appropriate articles;

For GS300 TESTS W/CODES

For SC300 TESTS W/CODES

For SC400 TESTS W/CODES

• Check fuel injector circuit.
• Check Volume Airflow (VAF) sensor circuit. See CODE 31 in appropriate article;

For GS300 TESTS W/CODES

For SC300 TESTS W/CODES

For SC400 TESTS W/CODES

• Check ECM back-up power circuit (battery).