Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Description & Operation
The switch monitor test uses PIDs to check operation of certain switches (and related circuits) that do not set codes.
- Turn ignition on. Connect New Generation Star (NGS) tester. Refer to EQUIPMENT HOOKUP . Using NGS tester, select PCM and enter PID/DATA MONITOR AND RECORD function.
- Select PIDs for switches in question. Operate switch while observing appropriate PID. If switch PID does not turn on and off when switch is operated, proceed with appropriate test. See SWITCH MONITOR TEST MODE table.SWITCH MONITOR TEST MODE
Switch Condition (NGS Reading) Test Vehicle Start (VST) Signal Ignition On (OFF); Ignition Start (ON) A Power Steering Pressure Switch (PSP SW) Engine Running, Steering In Neutral Position (OFF); Steering Turned (ON) FF A/C Switch (AC SW) Key On, A/C Off (OFF); A/C On (ON) KM Park/Neutral Position Signal (PNP) Key On, Gearshift Lever In "N" Or "P" Range (ON); Gearshift Lever Not In "N" & "P" Ranges (OFF) ..... A/C Relay (ACR) Engine Running, A/C Off (OFF); A/C On (ON) KM Cooling Fan Relay (Low) (LFAN) Engine Running, A/C Off (OFF); A/C On (ON) KF
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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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