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P1662

Cruise Control Inhibit Control Circuit.

  • Buick
  • Powertrain
  • Manufacturer code
  • Low severity

How this code is built

P
SystemPowertrain
1
Defined byThe manufacturer
6
AreaComputer and output circuits
62
FaultThe specific fault in that area

What it means

P1662 on a Buick means the powertrain control module has detected a fault in the cruise control inhibit control circuit. The module uses this circuit to switch cruise control off in certain conditions, and it set the code because the circuit's voltage or state did not match what it commanded. The exact circuit layout and test values depend on the model and year.

Symptoms

  • Cruise control will not engage or drops out unexpectedly
  • Cruise control indicator or message may show a fault
  • Check engine light or service vehicle soon light on
  • Cruise control works intermittently
  • Normal driving otherwise unaffected

Possible causes

  • Damaged, chafed or corroded wiring in the cruise inhibit control circuit (open circuit, short to earth or short to voltage)likely
  • Poor connection or corroded terminals at the powertrain control module or inline connectorslikely
  • Faulty brake pedal switch or related switch feeding or sharing the inhibit circuit (model dependent)possible
  • Faulty cruise control component the inhibit circuit drives or monitors, such as a relay or module (depends on model and engine)possible
  • Blown fuse or low supply voltage to the circuitpossible
  • Internal fault in the powertrain control modulerare

How to diagnose

  1. Read all stored codes and freeze frame data to see when the fault set and whether other codes are present
  2. Check the fuses for the cruise control and powertrain control circuits against the wiring diagram for the specific model
  3. Inspect the wiring and connectors for the inhibit circuit for chafing, heat damage, water ingress and corrosion
  4. Check the brake pedal switch operation and its adjustment, and look for related brake light faults
  5. Check battery condition and charging voltage, as low voltage can cause circuit faults
  6. Using the manufacturer wiring diagram, test the inhibit circuit for continuity, short to earth and short to voltage
  7. Check the voltage and earth supplies at the component the circuit controls, following model-specific procedures
  8. Clear the code and road test to confirm whether it returns

How to fix

  • Repair or replace damaged wiring in the inhibit circuit
  • Clean or repair corroded or loose connector terminals, or replace the connector
  • Replace a faulty brake pedal switch or other defective switch or relay in the circuit
  • Replace a blown fuse after finding and fixing the cause of the overload
  • Replace or reprogram the powertrain control module only after the wiring and components are proven good and the manufacturer procedure calls for it

Can I keep driving?

Low severity

The car can normally be driven as usual, as this fault mainly affects cruise control. Book it in for diagnosis soon, particularly if the brake lights or other systems are also behaving oddly.

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

This code for other makes

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