C1685 Engine Trouble Code
What is C1685?
When C1685 code appears, first check your gas cap. Pull over safely, ensure it is tight, and inspect for cracks. A loose or damaged gas cap affects fuel-system pressure and emissions. A replacement cap costs about $3–$10. This simple fix can resolve the code and improve fuel economy.
Code Information
| Code Type: | OBD-II Chassis (C) Trouble Code |
| System: | Chassis |
| Code: | C1685 |
C1685 Symptoms
Check Engine Light
Illuminated dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration
Starting Problems
Difficulty starting the engine
C1685 Code Structure
Understanding what each digit means in the C1685 chassis trouble code:
| C | 1 | 6 | 8 | 5 |
|---|---|---|---|---|
| Chassis Code | Fuel And Air Metering | Fuel Temperature Sensor B Circuit Range/Performance | Ignition/Distributor Engine Speed Input Circuit Malfunction | Crankshaft Position Sensor B Circuit Malfunction |
How to Fix C1685
Diagnostic Steps:
Oxygen sensors measure exhaust gas oxygen content to optimise air-fuel ratio. This optimisation improves fuel economy and reduces emissions. Sensors degrade over time and require periodic replacement.
Repair Solution:
Power steering pressure switch monitors system operation. If pressure changes are not detected after calibrated speed transitions, this DTC sets. Verify PSP switch operation and check for circuit opens or shorts.
Technical Notes:
C1685 DTCs can be triggered by upstream issues. For example, a dirty MAF sensor may cause incorrect fuel-trim adjustments, leading oxygen sensors to report mixture problems. Address root causes first.
C1685 Description
C1685 engine trouble code is related to Crankshaft Position Sensor B Circuit Malfunction.
Main Cause
The primary reason for C1685 OBD-II Engine Trouble Code is: Fuel Temperature Sensor B Circuit Range/Performance.