Riley Redwing C3378 Engine Trouble Code
What is Riley Redwing C3378?
When Riley Redwing C3378 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.
C3378 on the Riley Redwing
For Riley Redwing owners, diagnosing C3378 correctly requires ruling out a faulty camshaft position sensor before replacing more expensive components. The sensor wiring harness on this model runs close to the exhaust manifold and is prone to heat-related insulation damage.
Code Information
| Code Type: | OBD-II Chassis (C) Trouble Code |
| System: | Chassis |
| Vehicle: | Riley Redwing |
| Brand: | Riley |
| Model: | Redwing |
| Code: | C3378 |
C3378 Riley Redwing Symptoms
Check Engine Light
Illuminated Riley Redwing dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration on the Riley Redwing
Starting Problems
Difficulty starting the engine
Poor Fuel Economy
Increased fuel consumption on the Riley Redwing
Increased Emissions
Failed emissions test due to C3378
C3378 Code Structure
Understanding what each digit means in the C3378 chassis trouble code:
| C | 3 | 3 | 7 | 8 |
|---|---|---|---|---|
| Chassis Code | Ignition System Or Misfire | Throttle/Pedal Position Sensor/Switch A Circuit Intermittent | Cylinder 10 Contribution/Balance Fault | Clutch Position Sensor Circuit Malfunction |
How to Fix Riley Redwing C3378
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:
C3378 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.
Riley Redwing C3378 Repair Cost
Torque converter clutch solenoid replacement on the Riley Redwing — relevant for owners who tow regularly — costs $280–$480. A full transmission fluid change ($120–$160) at the same service is recommended because contaminated fluid accelerates solenoid wear.
C3378 Description
C3378 engine trouble code is related to Clutch Position Sensor Circuit Malfunction.
Main Cause
The primary reason for C3378 OBD-II Engine Trouble Code is: Throttle/Pedal Position Sensor/Switch A Circuit Intermittent.
Common C3378 Misdiagnosis on the Riley Redwing
On Riley Redwing vehicles, the turbo boost solenoid and the MAP sensor feed into the same diagnostic path. C3378 caused by a faulty boost solenoid is sometimes charged to the customer as a MAP sensor replacement, doubling unnecessary parts spend.
DIY Repair Guide: C3378 on Riley Redwing
The Riley Redwing EVAP purge solenoid valve is accessible without lifting the vehicle — it is mounted on the intake manifold and secured by a single bolt and a vacuum hose clip. DIY replacement is rated 1/5 difficulty and takes approximately 20 minutes.
Preventing C3378 on the Riley Redwing
After any fuel system repair on the Riley Redwing, always perform a fuel-trim reset and adaptation drive. Skipping this step leaves the ECU operating on pre-repair learned values, which can generate false C3378 alerts for weeks after the fix.
Frequently Asked Questions — Riley Redwing C3378
A: Yes. Any stored fault code — including C3378 — will cause an automatic failure in most OBD-II based emissions tests. The code must be resolved and the vehicle must complete a full OBD drive cycle with no new codes before the test.