What does it mean?
P1562 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Cruise Vacuum Solenoid Circuit Malfunction .
Symptoms
- Cruise control switches on but the vehicle will not hold or reach the set speed
- System cancels itself on the first gradient or under light load
- Set speed drifts downwards even on a flat road
- Cruise lamp flashes and the function locks out until the ignition is cycled
- Check engine light on with the code stored
Likely causes
- Open winding or an internal short in the vacuum solenoid
- Water intrusion and corrosion in the solenoid connector
- Damaged control wire between the cruise module and the solenoid, often chafed at a bulkhead grommet
- Lost ignition feed to the solenoid because of a blown fuse or a failed relay
- High resistance ground connection for the solenoid pack
- Perished vacuum hose, leaking reservoir or a failed one way valve starving the servo of vacuum
- Failed driver output in the control module
How to fix it
- Verify the basic inputs first: main switch, brake and clutch switches and a stable speed signal
- Inspect the connector and the harness at the servo for corrosion, chafing and moisture
- Measure the vacuum solenoid resistance and compare it with the vent solenoid in the same pack
- Check supply voltage and ground at the solenoid with the ignition on
- Apply vacuum to the servo with a hand pump and confirm that it holds and moves the linkage
- Check the vacuum supply hose, reservoir and one way valve for leaks and blockages
- Replace the solenoid or the servo when it fails the electrical or vacuum test, then road test to confirm the repair