Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
1993 Volvo 850 AutomaticFACTORY OEM SERVICE PROCEDURE
Trouble Code Identification
TROUBLE CODE DEFINITION (FUEL INJECTION SYSTEM) (1)
| Code | Fault/Repair | ||
|---|---|---|---|
| 1-1-1 | No Fault | ||
| 1-1-2 | Replace ECU | ||
| 1-1-3 | HO2S Integrator At Maximum Enrichment | ||
| 1-2-1 | MAF Sensor Signal Absent Or Faulty | ||
| 1-2-3 | Engine Temperature Sensor Signal Absent Or Faulty | ||
| 1-3-1 | Ignition System Speed Signal Absent Or Faulty | ||
| 1-3-2 | Battery Voltage Too High Or Too Low | ||
| 2-1-2 | HO2S Sensor Signal Absent Or Faulty | ||
| 2-2-1 | Adaptive HO2S Control, Engine Running Too Rich At Part Load | ||
| 2-2-3 | IAC Valve Signal Absent Or Faulty | ||
| 2-3-1 | Adaptive HO2S Control, Engine Running Too Lean At Part Load | ||
| 2-3-2 | Adaptive HO2S Control, Provides Richer Mixture At Idle | ||
| 3-1-1 | Speedometer Signal Absent Or Faulty | ||
| 4-1-1 | Throttle Switch Signal Absent Or Faulty | ||
| 5-1-1 | Adaptive HO2S Control, Provides Leaner Mixture At Idle | ||
| 5-1-2 | HO2S Integrator At Maximum Lean Running Limit | ||
|
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TROUBLE CODE DEFINITION (IGNITION SYSTEM) (1)
| Code | Fault/Repair | ||
|---|---|---|---|
| 1-1-1 | No Faults | ||
| 1-1-2 | Replace ECU | ||
| 1-2-3 | Engine Temp. Signal From Fuel Injection Absent Or Faulty | ||
| 1-3-1 | VSS Signal Absent | ||
| 1-4-3 | Front Knock Sensor Signal Absent Or Faulty | ||
| 1-4-4 | Load Signal From Fuel Injection Absent Or Faulty | ||
| 1-5-4 | EGR System Leakage | ||
| 2-1-4 | VSS Signal Intermittent | ||
| 2-4-1 | EGR Flow Incorrect | ||
| 3-1-1 | Speedometer Signal Absent Or Faulty | ||
| 3-1-4 | Camshaft Position Sensor Signal Absent Or Faulty | ||
| 3-2-4 | Camshaft Signal Intermittent | ||
| 4-1-1 | Throttle Switch Signal From Fuel Injection Absent Or Faulty | ||
| 4-1-3 | EGR Temperature Sensor Signal Incorrect/Missing | ||
| 4-3-2 | High Temperature Warning In ECU Box | ||
| 4-3-3 | Rear Knock Sensor Signal Absent Or Faulty | ||
| 5-1-3 | High Temperature Warning In ECU Box | ||
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Factory Service Tools
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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