Severity Medium
B1353

Key-In Circuit Open Code B1353

📅 Last reviewed: July 2026
What does the B1353 code mean?

Code B1353 indicates that the vehicle's control module (PCM or security module) has detected an open circuit in the Key-In signal circuit, which reports whether the ignition key is physically inserted into the ignition cylinder. This circuit typically uses a mechanical contact switch or Hall effect sensor located at the base of the steering column or in the ignition cylinder. When the circuit is open, the module cannot determine key presence, potentially affecting functions such as accessory power delay, anti-theft system (PATS), or automatic window closure. In Ford vehicles, this circuit is part of the Retained Accessory Power (RAP) system.

Medium
Severity
Variable
Typical Cost
Medium
Frequency

1. Commonly Affected Makes

FordLincolnMercury

2. Most Common Causes

3. Symptoms You Will Notice

4. Step-by-Step Diagnosis

1

Check for blown fuses related to the Key-In circuit

2

Inspect the Key-In switch and wiring for damage or corrosion

3

Test continuity of the Key-In signal wire from switch to control module

4

Verify proper operation of the Key-In switch using a multimeter

5

If all else is good, suspect a faulty control module

5. Frequently Asked Questions

Is it safe to drive?

Yes, the vehicle is generally safe to drive, but some convenience features like accessory power delay and anti-theft system may not work properly. It is recommended to diagnose and repair the issue to restore full functionality.

How much does it cost to fix?

The cost can range from $50 to $300 depending on the cause. A simple switch replacement may be around $50-$150, while wiring repairs or module replacement could be $200-$300 or more.

6. Related Codes

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