How to Fix Diagnostic Code P1585

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🚨 Diagnostic Profile

Vehicle Make: Chrysler

Description: Cruise Inhibit Control Circuit fault. The cruise control system has detected a condition or signal that is preventing cruise engagement or causing it to disengage. This is typically related to brake, clutch, or cruise switch inputs, or to the control module that processes them.

🚨 Repair Difficulty Tier

Tier: Intermediate

Most causes involve switch adjustment, switch replacement, or wiring continuity checks. Diagnosis requires a scan tool with live data and a digital multimeter. Module or wiring repairs may require professional-level access and programming.

🛠️ Resolution Steps

Step 1: Preliminary Inspection

  • Verify the customer complaint and confirm the exact conditions under which cruise inhibits (for example, at all speeds, only after braking, or only in certain gears).
  • Inspect the brake pedal position switch and stop lamp switch for physical damage, loose connectors, and proper plunger travel against the pedal bracket.
  • Inspect the clutch pedal position switch on manual transmission vehicles for proper adjustment and connector integrity.
  • Inspect the cruise control switches on the steering wheel or column stalk for sticking, water intrusion, or damaged connectors.
  • Check the brake fluid level and condition, and confirm there are no active ABS or brake system warning lamps, since many Chrysler PCM/BCM strategies inhibit cruise if a brake fault is present.
  • Inspect wiring harnesses and connectors at the brake switch, clutch switch, cruise switch, and control module for corrosion, pushed-back pins, or chafing, particularly near the steering column connector and under-dash harness routing.
  • Confirm battery state of charge and check for any stored charging system or low-voltage faults that could cause the PCM or BCM to set a cruise inhibit condition.

Step 2: Diagnostic Verification

  • Connect a scan tool (factory-level Chrysler diagnostic software such as wiTECH, or a quality aftermarket scanner with enhanced Chrysler data) and read stored and pending diagnostic trouble codes from the PCM, BCM, and SKIM/cluster if cruise control logic is shared across modules.
  • Record freeze frame data for the cruise inhibit fault, including vehicle speed, engine speed, brake switch state, and cruise switch state at the time of the fault.
  • Monitor live data parameters for Brake Switch Status, Cruise Control Switch Status, and Clutch Switch Status (if equipped) while actuating each pedal and button through its full range of travel.
  • Confirm that the brake switch shows two complementary circuits (normally open and normally closed, depending on model) changing state correctly and in sync when the pedal is pressed and released; a mismatch between redundant brake signals is a common cause of cruise inhibit on Chrysler products.
  • Check switch circuit voltage and continuity using a digital multimeter: with the connector backprobed, confirm reference voltage (typically 5V or 12V system voltage depending on circuit) is present at the switch supply circuit, and that voltage toggles correctly between open and closed switch positions.
  • Verify ground integrity at the control module and switch ground circuits by measuring voltage drop between the ground pin and a known good chassis ground; a reading of less than 0.2V under load indicates an acceptable ground.
  • Perform a wiggle test on harnesses and connectors while monitoring live data and watching for signal dropout to help locate intermittent opens or shorts.

Step 3: Resolution & Reset Process

  • Adjust or replace the faulty brake switch, clutch switch, or cruise switch, as determined by diagnostic results.
  • Repair any open, shorted, or corroded circuits and replace damaged connector terminals using approved solder-and-heat-shrink or factory terminal repair procedures; avoid simple twist-and-tape splices.
  • Replace the control module (PCM or BCM) only if all inputs and wiring have been verified and the module is confirmed faulty. Reprogram or flash the module using Chrysler-approved software if required, and perform any necessary module configuration or VIN re-sync per service information.
  • Clear all diagnostic trouble codes with the scan tool.
  • Perform a road test to confirm cruise control engages, holds set speed, resumes correctly, and does not inhibit under normal acceleration, braking, and gear changes.
  • Recheck for stored or pending codes after the road test and document the final repair and test results for the customer record.

📦 Parts, Labor, and Budget Estimates

Required Components/Software:

  • Brake pedal position switch or stop lamp switch assembly (dealer or OE-equivalent part, vehicle-specific)
  • Clutch pedal position switch (manual transmission only, vehicle-specific)
  • Cruise control switch assembly or steering wheel control module (vehicle-specific)
  • PCM or BCM control module, only if confirmed faulty (requires VIN-specific programming)
  • Connector terminals, harness repair splice kit, heat-shrink, and dielectric grease as needed for wiring repair
  • Factory-level scan tool (such as wiTECH/StarMOBILE) or professional-grade aftermarket scanner with bi-directional and live-data capability for Chrysler vehicles

Average Component Price:

  • Brake or stop lamp switch: $20–$60 (parts only)
  • Clutch pedal position switch: $35–$90 (parts only)
  • Cruise control switch assembly or stalk: $60–$200 (parts only)
  • PCM or BCM control module: $400–$1,200 (parts only, before programming fees)
  • Miscellaneous wiring repair materials (terminals, splice kits, loom): $15–$50
  • Dealer or specialty programming fee (if module replacement required): $100–$250

Estimated Labor Hours:

  • Diagnosis and verification (scan tool, live data, multimeter testing): 0.8–1.5 hours
  • Switch replacement or adjustment (brake, clutch, or cruise switch): 0.3–0.8 hours per switch
  • Wiring repair (harness or connector, depending on access and location): 0.5–2.0 hours
  • Module replacement and programming (PCM or BCM, if required): 1.0–2.5 hours
  • Road test and final verification: 0.3–0.5 hours

Estimated Total Repair Range: Switch-related repairs typically range $100–$350 including labor and parts. Wiring repairs typically range $150–$400. Module replacement with programming typically ranges $600–$1,700 including parts, labor, and programming fees, depending on dealer versus independent shop rates and regional labor costs.