The C1420 OBD2 fault code relates to the Hydraulic Fluid Pressure/Flow circuit. This is part of the vehicle's chassis control system. When the short to battery, the control module cannot properly monitor or regulate this system, which may affect braking, traction, stability, or suspension performance.
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Symptoms
- System warning light
- Intermittent operation
- Possible module communication issues
Common Causes
- Faulty component — internal damage or wear affecting the Hydraulic Fluid Pressure/Flow
- Wiring issues — broken, corroded, or chafed wires in the circuit
- Connector problems — loose, oxidized, or moisture-damaged pins
- a short to battery voltage is detected — connects the signal line directly to 12V, causing constant high voltage
- Control module fault — rare, but the chassis control module may have an internal fault
Step-by-Step Diagnosis
- Scan with OBD2 tool — Confirm C1420 is active. Check for additional chassis DTCs.
- Visual inspection — Examine the Hydraulic Fluid Pressure/Flow wiring and connector for corrosion or damage.
- Check voltage and ground — Use a multimeter to verify proper reference voltage.
- Test component — Compare readings to factory specs. A stuck or erratic signal confirms failure.
- Check for shorts/opens — Perform continuity tests on the wiring between the component and control module.
Repair & Solutions
- If the component is defective, replace the Hydraulic Fluid Pressure/Flow with an OEM or quality aftermarket part.
- Repair any damaged wiring or connectors using proper methods.
- Clear the DTC with an OBD2 scanner and test drive to verify the code does not return.
- If the code persists after component replacement, inspect the control module connector or consider module testing.
Related Codes
- C1417 — Damper RF Circuit Short to Ground
- C1418 — Damper RF Circuit Failure
- C1419 — Damper RF Circuit Open
External References & Forum Discussions
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