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DTC codes / Chrysler codes / P1585

P1585 · ChryslerCruise Inhibit Control Circuit

P1585 on Chrysler vehicles indicates that the powertrain control module (PCM) has detected an electrical fault in the cruise inhibit control circuit, which is the path the PCM uses to determine whether cruise control should be allowed to engage. The PCM monitors this circuit for unexpected voltage or continuity and sets the code when the signal does not match the expected state for the current driving conditions.

SystemPowertrain
Code typeChrysler specific
SeverityLow
Fix difficultyIntermediate
AreaVehicle speed, idle control and auxiliary inputs

Symptoms you may notice

  • Cruise control will not engage or cancels immediately after being set
  • Cruise indicator lamp on the instrument cluster may flash or stay off when the button is pressed
  • Often no symptoms besides the warning light, with the vehicle driving normally otherwise
  • Speed control buttons on the steering wheel may feel unresponsive
  • In some cases the engine may idle slightly higher or lower than usual if the inhibit signal is misread

Common causes, most likely first

  1. Faulty brake pedal position switch or clutch pedal switch (on manual transmission vehicles) sending an incorrect inhibit signal
  2. Damaged or corroded wiring in the cruise inhibit circuit, especially at the brake switch connector or PCM harness
  3. Failed cruise control servo or module that cannot communicate the inhibit status correctly
  4. Defective clock spring in the steering wheel causing intermittent button signals
  5. PCM software glitch or internal driver fault for the inhibit circuit
  6. Aftermarket alarm or remote start installation tapping into the brake or cruise wiring

How to diagnose and fix it

  1. Connect a scan tool and read live data for the cruise inhibit switch status while pressing and releasing the brake pedal to confirm the PCM sees the correct signal
  2. Inspect the brake pedal switch and clutch pedal switch (if equipped) for proper adjustment, corrosion, or loose connectors
  3. Check the wiring harness from the brake switch to the PCM for chafing, pinched wires, or green corrosion at the terminals
  4. Test the cruise control servo and its connector for power, ground, and signal integrity according to the factory service information
  5. Verify the clock spring and steering wheel buttons by checking resistance and continuity through the spiral cable
  6. If all external circuits test good, reflash or replace the PCM only after confirming no other faults are present

Cruise inhibit circuit checks that save time

  • A misadjusted brake pedal switch is the most common cause of P1585 on Chrysler vehicles, and it often does not affect the brake lights, so a visual check of the lamps is not enough.
  • The code can set intermittently from a worn clutch pedal switch on manual transmission models, and the driver may never notice because cruise control still works most of the time.
  • Aftermarket accessories wired into the brake circuit, such as trailer brake controllers or remote starters, frequently introduce the voltage irregularity that triggers this code.
  • P1585 does not always mean the cruise servo is bad; the PCM sets it based on the inhibit input, so a perfectly good servo can be replaced unnecessarily if the switch circuit is not tested first.
  • On some Chrysler models the cruise inhibit signal passes through the totally integrated power module (TIPM), so a TIPM fault or a loose ground at the module can set P1585 without any problem in the steering wheel or servo.

Can I keep driving with P1585?

The vehicle remains safe to drive because the fault only disables cruise control, but you should avoid using cruise control until the circuit is repaired. Do not ignore the warning light if you rely on cruise control for long trips, and have the brake switch circuit checked promptly.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for Chrysler vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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