P1708 Brake Switch Signal Out of Range
The P1708 code indicates that the brake switch signal is outside the expected range during the PCM or transmission control module self-test. The PCM uses the brake switch to confirm pedal release before allowing gear shifts (shift lock) and to disengage cruise control. During self-diagnosis, the module checks circuit integrity; if voltage or resistance doesn't match preset parameters in the resting or activated state, this code sets. This typically occurs due to a misadjusted or faulty brake switch, a short circuit, or the brake pedal not being in its correct rest position during the scan.
01. Most Common Causes
- Misadjusted or defective brake light switch
- Short to voltage or ground in the brake switch circuit
- Corroded or bent pins in the brake switch connector
- Open or shorted wiring in the brake switch circuit
- Brake pedal mechanically stuck or not returning fully to rest position
- Blown brake light circuit fuse
- Internal PCM failure
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Cruise control inoperative
- Shift lock malfunction (unable to shift out of Park)
- Brake lights may not work or stay on constantly
03. Step-by-Step Diagnosis
Verify brake lights operate correctly; check for stuck pedal or misadjusted switch.
Inspect brake switch connector for corrosion, bent pins, or damage.
Test brake switch continuity and voltage supply with a multimeter.
Check for blown fuse in the brake light circuit.
If all else passes, suspect internal PCM fault and perform further module testing.
1. Frequently Asked Questions
Is it safe to drive?▼
It is moderately safe for short trips, but you may lose cruise control and have difficulty shifting out of Park. Have it diagnosed soon to avoid potential transmission issues.
How much does it cost to fix?▼
Typically $100 to $300 for a brake switch replacement, including parts and labor. If wiring or PCM repair is needed, costs can exceed $500.