C0842 Engine Trouble Code
What is C0842?
C0842 code can indicate a faulty oxygen sensor, which may eventually damage the catalytic converter (repair cost: $2,000–$2,200). Professional diagnosis costs around $200–$210. Oxygen sensors are often straightforward to replace — check your owner's manual for location and instructions. This issue should be addressed promptly to prevent further damage.
Code Information
| Code Type: | OBD-II Chassis (C) Trouble Code |
| System: | Chassis |
| Code: | C0842 |
C0842 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
C0842 Code Structure
Understanding what each digit means in the C0842 chassis trouble code:
| C | 0 | 8 | 4 | 2 |
|---|---|---|---|---|
| Chassis Code | Intake Valve Control Solenoid Circuit Low | Engine Oil Temperature Sensor Malfunction | Injection Pump Fuel Metering Control 'B' High | Glow Plug/Heater Circuit 'A' Malfunction |
How to Fix C0842
Diagnostic Steps:
Regarding C0842, carefully inspect the wire harness near the intake manifold bracket, best accessed from below near the oil filter. Look for chafing, pinching, or damaged insulation.
Repair Solution:
Excessive air inflow may result from vacuum leaks, dirty sensors, or EGR valves not closing properly. Insufficient fuel can stem from dirty injectors, clogged filters, weak fuel pump, or leaking pressure regulator.
Technical Notes:
C0842 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.
C0842 Description
C0842 engine trouble code is related to Glow Plug/Heater Circuit 'A' Malfunction.
Main Cause
The primary reason for C0842 OBD-II Engine Trouble Code is: Engine Oil Temperature Sensor Malfunction.