P1561
Cruise Vent Solenoid.
- Oldsmobile
- Powertrain
- Manufacturer code
- Low severity
How this code is built
- P
- SystemPowertrain
- 1
- Defined byThe manufacturer
- 5
- AreaVehicle speed, idle control and auxiliary inputs
- 61
- FaultThe specific fault in that area
What it means
On an Oldsmobile, P1561 relates to the cruise vent solenoid circuit, which is part of the vacuum-operated cruise control system. The vent solenoid releases vacuum from the cruise servo so the throttle returns when cruise is cancelled. The control unit sets the code when it sees a fault in the solenoid's electrical circuit, such as an open circuit, short or wrong voltage. The exact circuit and test method depend on the model and year.
Symptoms
- Cruise control will not engage or cuts out unexpectedly
- Cruise control will not release promptly when braking or cancelling
- Cruise control warning or service light on, where fitted
- Engine management light on
- Cruise speed hunting or surging on a steady throttle
Possible causes
- Damaged, chafed or corroded wiring to the cruise vent solenoidlikely
- Loose, corroded or damaged connector at the solenoid or control unitlikely
- Faulty cruise vent solenoid (open or shorted coil)possible
- Vacuum leak or split hose in the cruise servo circuit affecting operationpossible
- Faulty brake switch or related cruise control input upsetting the circuitrare
- Fault within the control unit driver circuitrare
How to diagnose
- Read the stored codes and freeze frame data, note any other cruise or brake switch codes, then clear and see if P1561 returns
- Visually inspect the cruise vent solenoid, its wiring and connector for chafing, heat damage, corrosion or water ingress
- Check the vacuum hoses to the cruise servo and solenoid for splits, perforations and loose fittings
- Check fuse supply and the power and ground feeds to the solenoid against the wiring diagram for your model
- Measure the solenoid coil resistance and compare it with the manufacturer specification for your model
- Check the wiring between the solenoid and control unit for continuity, short to ground and short to voltage
- Command the solenoid with a suitable scan tool, if supported, and listen for it clicking or check the control signal
- Only if all wiring and the solenoid test good, investigate the control unit driver circuit
How to fix
- Repair or replace damaged wiring and fix any open or short circuits found
- Clean, reseat or replace faulty connectors and terminals
- Replace the cruise vent solenoid if its resistance or operation is out of specification
- Replace split or leaking vacuum hoses and refit loose connections
- Repair or replace the control unit only after the circuit and solenoid are proven good
Can I keep driving?
Low severity
The car is normally safe to drive, but cruise control may be unavailable or unreliable. Avoid using cruise until repaired and book it in at your convenience.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.