P0566

Code

Generic P — Powertrain

Cruise Control Off Signal

Brand: Generic

Type: P — Powertrain

Views: UK: 30 EN: 39 RU: 35

AI status

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Page language: EN

Causes

Open or short in cruise off switch wiring or connector
Defective cruise control off switch (stuck, dirty, or mechanically failed)
Corroded or loose connector pins at the switch or PCM
Incorrect reference/pull‑up voltage (faulty resistor or short to battery/ground)
Blown fuse or loss of module power/ground affecting the input circuit
Intermittent faults (broken wire, chafing) causing transient signal

Symptoms

Cruise control inoperative or disabled
Cruise warning or OFF lamp illuminated
DTC P0566 stored in PCM and possibly cruise-related messages displayed
Intermittent loss of cruise control function
No obvious switch movement feedback when using cruise controls

What to check

Retrieve freeze frame and live data with a scan tool; confirm P0566 set and monitor cruise off input status
Visually inspect the cruise switch, wiring harness, and connectors for damage, corrosion, or water entry
Verify fuses and power/ground integrity for cruise control and PCM circuits
Check continuity and resistance of switch and wiring (switch open/closed states)
Backprobe the switch connector and monitor voltage while operating the switch
Wiggle test harness while monitoring live data to locate intermittent wiring faults

Signal parameters

Signal type: typically a discrete digital input (switch to ground or switched 12 V) or low-voltage logic (0–5 V) depending on vehicle
Expected low/ground: ~0–0.5 V when pulled to ground
Expected high/pull‑up: ~4–5 V (logic) or battery voltage if switched to 12 V
Open-circuit: no connection (voltage may float or show pull‑up value); short-to-ground: ~0 V; short-to-battery: ~battery voltage
Switch continuity: near 0 ohms closed, OL or high resistance when open (confirm with service spec)

Diagnostic algorithm

Connect a scan tool. Confirm P0566 is current or stored and note freeze-frame data and related codes.
With ignition ON (engine off unless specified by manufacturer), observe the cruise off input parameter while operating the cruise off switch. Note expected state change.
Visually inspect switch and connector for damage, corrosion, or loose pins. Repair or replace any visibly damaged components.
Backprobe the switch connector. Measure voltage at the signal pin with switch OFF and ON. Compare to expected logic levels (see signal_params).
If signal is missing or incorrect, check for proper reference/pull‑up voltage at the switch feed and verify ground continuity to chassis/PCM.
Test switch continuity with a multimeter: verify open when in one position and closed in the other per service spec. Replace switch if out of specification.
Check wiring continuity between the switch and the PCM connector. Repair any opens, shorts, or high-resistance sections. Use insulation repair methods or splice kits for harness repair.
Perform a wiggle test on harnesses while monitoring the input to find intermittent faults; repair or secure harness accordingly.
If wiring and switch test good, inspect PCM connector pins for corrosion or damage. If input still incorrect, consider PCM diagnostic procedures (reprogramming or internal fault testing) per manufacturer guidance.
Clear codes and retest. Confirm cruise control operation and monitor for reoccurrence before road testing.

Likely causes

Failed cruise control off switch at steering column or stalk
Wiring harness damage or connector corrosion between switch and PCM
Open/short to battery or ground on the switch feed or signal return
Poor ground or low system voltage affecting logic signals
Intermittent connector contact (water intrusion, bent pins)

Fault status

⚠️ Status

PCM detected invalid or absent 'Cruise Control Off' input (P0566). Cruise control may be disabled. Code stored; use scan tool to view input state and related data.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours