Mercedes Sl 350 C0822 Engine Trouble Code
What is Mercedes Sl 350 C0822?
Mercedes Sl 350 C0822 indicates potential catalytic converter failure. If completely failed, your vehicle may not run properly and fuel economy will suffer significantly. Average replacement cost is $2,000–$2,140. This repair requires professional service and should not be delayed.
C0822 on the Mercedes Sl 350
Owners of the Mercedes Sl 350 should be aware that C0822 can appear alongside oil consumption warnings. Low oil pressure caused by a worn PCV system lets crankcase vapour contaminate the mass air flow sensor, sending erroneous readings to the ECU.
Code Information
| Code Type: | OBD-II Chassis (C) Trouble Code |
| System: | Chassis |
| Vehicle: | Mercedes Sl 350 |
| Brand: | Mercedes |
| Model: | Sl 350 |
| Code: | C0822 |
C0822 Mercedes Sl 350 Symptoms
Check Engine Light
Illuminated Mercedes Sl 350 dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration on the Mercedes Sl 350
Starting Problems
Difficulty starting the engine
Poor Fuel Economy
Increased fuel consumption on the Mercedes Sl 350
Increased Emissions
Failed emissions test due to C0822
C0822 Code Structure
Understanding what each digit means in the C0822 chassis trouble code:
| C | 0 | 8 | 2 | 2 |
|---|---|---|---|---|
| Chassis Code | Intake Valve Control Solenoid Circuit Low | Engine Oil Temperature Sensor Malfunction | Turbocharger Boost Sensor A Circuit Low | Glow Plug/Heater Circuit 'A' Malfunction |
How to Fix Mercedes Sl 350 C0822
Diagnostic Steps:
The catalytic converter has oxygen sensors before and after it. When warm and in closed-loop mode, the upstream O2 sensor reading should fluctuate, while downstream should remain steady.
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:
C0822 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.
Mercedes Sl 350 C0822 Repair Cost
Torque converter clutch solenoid replacement on the Mercedes Sl 350 — 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.
C0822 Description
C0822 engine trouble code is related to Glow Plug/Heater Circuit 'A' Malfunction.
Main Cause
The primary reason for C0822 OBD-II Engine Trouble Code is: Engine Oil Temperature Sensor Malfunction.
Common C0822 Misdiagnosis on the Mercedes Sl 350
Some Mercedes Sl 350 models have a known software bug where the PCM flags C0822 after battery disconnection and reconnect. Always perform an ECU adaptation reset and drive cycle before ordering any parts following battery work.
DIY Repair Guide: C0822 on Mercedes Sl 350
After any repair that involved disconnecting the battery on the Mercedes Sl 350, the power window, steering angle sensor, and transmission adaptive values all require a reset drive cycle. Skipping this can cause false fault codes — including C0822 — for the first two to three start cycles.
Preventing C0822 on the Mercedes Sl 350
For turbocharged Mercedes Sl 350 models, allowing the engine to idle for 60–90 seconds before shutdown after hard driving reduces turbocharger heat soak and prevents the coking of oil that blocks VVT galleries — a known secondary trigger of C0822.
Frequently Asked Questions — Mercedes Sl 350 C0822
A: If your Mercedes Sl 350 is within the factory powertrain warranty period (typically 3–5 years or 60,000–100,000 miles depending on region and generation), C0822 repairs caused by component defects should be covered. Bring your service history to the dealer appointment.