P2536

Code

Generic P — Powertrain

Ignition Switch Accessory Position Circuit

Brand: Generic

Type: P — Powertrain

Views: UK: 37 EN: 55 RU: 34

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Page language: EN

Causes

Faulty ignition switch (worn or failed ACC contact)
Open, shorted, or damaged wiring on the ACC circuit
Corroded or loose connector or terminal at the ignition switch or control module
Poor ground connection or high resistance in circuit
Failed Body Control Module (BCM) / Powertrain Control Module (PCM) input circuit
Aftermarket accessories or alarms interfering with ACC circuit

Symptoms

Accessories (radio, power windows, HVAC blower) do not power in ACC position or work intermittently
Dash indicators or interior lights may not come on with key in ACC
Erratic accessory operation or sudden loss of accessory power
Malfunction indicator lamp or stored codes related to accessory/ignition circuits
Possible no-crank or no-start behaviors if circuit affects starter control (vehicle dependent)

What to check

Verify battery voltage is normal (approx. 12–14V) before testing
Scan for stored codes and freeze-frame data; check for related codes
Visually inspect ignition switch, connector, wiring harness, and fuses for damage or corrosion
Wiggle test wiring and connector while observing live data or voltages to reproduce fault
Check continuity and resistance between ignition switch ACC terminal and receiving module pin
Measure ACC circuit voltage at the ignition switch and at the module with key OFF and ACC positions

Signal parameters

ACC circuit expected voltage: near battery voltage (~11–14 V) when key in ACC (vehicle dependent)
ACC circuit expected voltage: near 0 V (or open) with key OFF
Signal should be steady with the key held in ACC (no rapid spikes, drops, or intermittent open)
Closed contact resistance across ACC switch contacts: very low (
No short to ground (

Diagnostic algorithm

Confirm code P2536 is current or stored and note freeze-frame data; check for other related codes.
Verify battery voltage and condition; poor battery can cause erratic inputs—correct if necessary.
Inspect ignition switch and harness visually for damage, corrosion, or loose connectors; repair visible issues.
With key OFF and ACC, measure voltage at ignition switch ACC terminal to establish baseline (should be ~0V OFF, ~battery V in ACC).
Turn key to ACC and measure voltage at the receiving module (BCM/PCM) ACC input pin. Compare to voltage at switch to identify where signal is lost.
Perform continuity check between ignition switch ACC terminal and module ACC input. Repair any open circuit.
Check for shorts: with power removed, measure resistance from ACC circuit to ground and to constant battery feed to find unintended connections.
Wiggle test wiring/connectors while monitoring voltage/data to reproduce intermittent faults; inspect for pin damage or corrosion.
If wiring and connectors are good, bench-test or replace the ignition switch assembly per service manual procedures.
If switch and wiring are confirmed good, test or replace the receiving module input circuit (BCM/PCM) only after verifying wiring and connectors.
After repairs, clear codes, cycle ignition through positions, and road/test to confirm repair; re-scan for reoccurrence.

Likely causes

Loose or corroded connector at the ignition switch
Worn ignition switch ACC contact (common with high-mileage switches)
Damaged wire harness (chafing, pinched, or broken conductor) between switch and module
Short to ground or short to battery power on ACC feed
High-resistance connection at fuse, relay, or inline connector

Fault status

⚠️ Status

Control module detected an invalid or intermittent signal on the ignition switch ACC position circuit — possible open, short, high resistance, or faulty ignition switch/contact.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours