Air Suspension Disable Switch Circuit High Voltage
The C1842 code indicates that the air suspension control module has detected excessive voltage on the air suspension disable switch circuit, consistent with a short to battery positive (B+). This switch allows the driver to manually disable the compressor and height adjustment. A short to battery prevents the module from correctly interpreting the switch state, which may keep the system disabled or trigger warning lights on the instrument panel.
1. Commonly Affected Makes
2. Most Common Causes
- Faulty air suspension disable switch with internal short
- Wiring short to battery positive in the switch circuit
- Damaged, corroded, or bent connector pins causing a bridge between signal and voltage
- Internal short in the air suspension control module (less common)
3. Symptoms You Will Notice
- Air suspension system remains disabled or inoperative
- Warning light on the instrument panel (e.g., 'Suspension Fault')
4. Step-by-Step Diagnosis
Scan for codes and verify C1842 is present
Inspect the air suspension disable switch and its connector for damage or corrosion
Check for voltage on the switch signal wire with the switch disconnected; if voltage is present, trace short to B+
Test switch continuity: should be open when not pressed, closed when pressed
If wiring and switch are good, suspect the air suspension control module
5. Frequently Asked Questions
Is it safe to drive?▼
Yes, but the air suspension may not function, affecting ride height and comfort. Have it diagnosed soon to avoid further issues.
How much does it cost to fix?▼
Typically $100-$300 for switch replacement, $150-$400 for wiring repair, or $500-$1000+ for module replacement.