504 Generic diagnostic codes on file — with the full diagnosis, repair steps, and field insights open to read free, no signup required.
Disclaimer: General reference information for trained, qualified technicians only. Codes and procedures vary by model, serial number and software version. Always follow the manufacturer's service manual and your site's safety procedures. Use at your own risk. Not affiliated with or endorsed by any manufacturer.
| Code | System | Symptom | Full fix |
|---|---|---|---|
| P0140 | Emissions | MIL On / Catalyst Test Incomplete | View fix |
| P0141 | Emissions | MIL On / Slow System Readiness | View fix |
| P0142 | Emissions | MIL On | View fix |
| P0143 | Emissions | MIL On | View fix |
| P0144 | Emissions | MIL On | View fix |
| P0145 | Emissions | MIL On | View fix |
| P0146 | Emissions | MIL On | View fix |
| P0147 | Emissions | MIL On | View fix |
| P0150 | Emissions | Engine Runs Rough / High Emissions | View fix |
| P0151 | Emissions | Engine Hesitation / Surging | View fix |
| P0152 | Emissions | Black Smoke / Misfires | View fix |
| P0153 | Emissions | Slow Fuel Trim Shifts | View fix |
| P0154 | Emissions | Open Loop on Bank 2 Only | View fix |
| P0155 | Emissions | Slow Engine Closed-Loop Step | View fix |
| P0156 | Emissions | MIL On | View fix |
| P0157 | Emissions | MIL On | View fix |
| P0158 | Emissions | MIL On | View fix |
| P0159 | Emissions | MIL On | View fix |
| P0160 | Emissions | MIL On | View fix |
| P0161 | Emissions | MIL On | View fix |
| P0162 | Emissions | MIL On | View fix |
| P0163 | Emissions | MIL On | View fix |
| P0164 | Emissions | MIL On | View fix |
| P0165 | Emissions | MIL On | View fix |
| P0166 | Emissions | MIL On | View fix |
| P0167 | Emissions | MIL On | View fix |
| P0170 | Fuel System | Engine Hunting / Poor Power | View fix |
| P0171 | Fuel System | Rough Idle / Lean Stumble | View fix |
| P0171 | Air Intake | Poor Acceleration / Lean | View fix |
| P0171 | Fuel System | Rough Idle / Lean Stumble | View fix |
| P0172 | Fuel System | Black Smoke / Fuel Smells | View fix |
| P0173 | Fuel System | Engine Surges on Deceleration | View fix |
| P0174 | Fuel System | Lean Shudder under Load | View fix |
| P0175 | Fuel System | Misfires / Spark Plug Sooting | View fix |
| P0176 | Fuel System | Stumble on Flex-Fuel Startups | View fix |
| P0177 | Fuel System | Poor Acceleration with E85 Fuel | View fix |
| P0178 | Fuel System | MIL On / Default Trim Maps | View fix |
| P0179 | Fuel System | MIL On / Rough Running | View fix |
| P0180 | Fuel System | MIL On Only | View fix |
| P0181 | Fuel System | MIL On / Hard Hot Starts | View fix |
| P0182 | Fuel System | MIL On | View fix |
| P0183 | Fuel System | MIL On | View fix |
| P0184 | Fuel System | Intermittent Stumble on Grade Changes | View fix |
| P0185 | Fuel System | MIL On Only | View fix |
| P0186 | Fuel System | MIL On | View fix |
| P0187 | Fuel System | MIL On | View fix |
| P0188 | Fuel System | MIL On | View fix |
| P0189 | Fuel System | Erratic Instrument Cluster Readout | View fix |
| P0190 | Fuel System | No Start / Limp Mode Warning | View fix |
| P0191 | Fuel System | Limp Mode / Hard Start Under Load | View fix |
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