KM71 - Check Low Pressure Switch

- Key "OFF".

- Low Pressure (LP) switch disconnected.

- Measure resistance between chassis ground and both pins of LP switch.

- Are both resistances greater than 10,000 ohms?

Yes -- Go to KM72. KM72 - Check ACD Circuit to PCM For Short to Ground

No -- Replace LP switch. Reconnect all components. Re-evaluate symptom.