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GTECH Calibration
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P1562

Cruise Vacuum Solenoid.

  • Cadillac
  • Powertrain
  • Manufacturer code
  • Low severity

How this code is built

P
SystemPowertrain
1
Defined byThe manufacturer
5
AreaVehicle speed, idle control and auxiliary inputs
62
FaultThe specific fault in that area

What it means

P1562 on a Cadillac relates to the cruise control vacuum solenoid circuit. The control unit monitors the solenoid and its driver circuit, and sets the code when the electrical readings do not match what it commanded, for example an open circuit, a short or an unexpected voltage. The exact test and thresholds depend on the model and year, so check the manufacturer data for the vehicle in question.

Symptoms

  • Cruise control will not engage or drops out unexpectedly
  • Cruise control behaves erratically or surges while active
  • Cruise control indicator or related warning light may show
  • Check engine light on with the code stored
  • Brake switch or cruise related functions may seem unresponsive

Possible causes

  • Faulty cruise vacuum solenoid (open or shorted coil)likely
  • Damaged wiring, chafing or corrosion in the solenoid circuitlikely
  • Loose, corroded or damaged connector at the solenoid or control unitlikely
  • Blown fuse or poor power or earth supply to the cruise circuitpossible
  • Vacuum leak or damaged vacuum line or actuator affecting the cruise systempossible
  • Fault in the control unit driver circuitrare

How to diagnose

  1. Read all stored codes and freeze frame data, noting any other cruise, brake switch or battery voltage faults
  2. Check the relevant fuse and confirm the battery is healthy and the charging voltage is correct
  3. Visually inspect the solenoid wiring and connectors for chafing, heat damage, corrosion and water ingress
  4. Inspect the vacuum lines and actuator for splits, disconnections or leaks
  5. Measure the solenoid coil resistance and compare it with the manufacturer specification for the model
  6. Check for power and earth at the solenoid connector with the ignition on, following the wiring diagram
  7. Test the circuit for continuity and shorts between the solenoid and the control unit
  8. Clear the code and road test, checking whether it returns and under what conditions

How to fix

  • Replace the cruise vacuum solenoid if its resistance or operation is out of specification
  • Repair or replace damaged wiring and clean or replace faulty connectors
  • Replace the fuse only after finding and correcting the cause of the failure
  • Repair or replace leaking or damaged vacuum lines or the actuator
  • Restore a good power or earth connection to the circuit
  • Have the control unit checked and repaired or replaced only if all wiring and components test correct

Can I keep driving?

Low severity

The car can normally be driven, as this fault usually only affects the cruise control. Book it in for diagnosis at your convenience, and avoid relying on cruise control until it is repaired.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.

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