When your Mercury’s “check engine” light comes on, it’s usually accompanied by a cryptic code like P0171, which indicates a system running too lean. But what does that really mean, and how do you fix it? You’re likely dealing with a faulty oxygen sensor or vacuum leak, but without the right tools, you’re stuck guessing.
That’s where OBD/OBD2 codes come in – a standardized system that helps you pinpoint the problem and get your car running smoothly again. But with so many codes and possible causes, where do you even start?
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Understanding OBD-II Codes
Understanding the fundamentals is crucial for efficient diagnosis and repair as you delve into the world of Mercury OBD-II codes.
The OBD-II system is a self-diagnostic tool that uses Diagnostic Trouble Codes (DTCs) to indicate specific component issues in your vehicle. These codes are structured into four main groups: P (Powertrain), B (Body), C (Chassis), and U (Network Communication).
The P codes deal with the powertrain system, including the engine, transmission, and drivetrain accessories. They are further divided into subsets, such as fuel and air metering, fuel injector circuit issues, and engine misfiring issues.
Retrieving and Interpreting Codes
When you’re ready to diagnose an issue with your Mercury vehicle, retrieving and interpreting OBD-II codes is a crucial step.
Plug a code reader or scan tool into the OBD-II port, usually located under the steering column, to retrieve the codes.
The code reader will display a five-digit code, with the first character indicating the associated vehicle system (such as P for powertrain or B for body) and the remaining characters providing specific information about the problem.
Consult your vehicle’s repair manual or a reliable online resource to interpret the code, as some may have manufacturer-specific definitions.
Once you’ve retrieved and interpreted the code, address the underlying issue promptly to prevent further damage or safety risks.
Common Mercury OBD-II Codes
Your Mercury vehicle’s onboard computer has stored a wealth of information in the form of OBD-II codes, waiting to be deciphered and addressed.
These Diagnostic Trouble Codes (DTCs) can help you identify issues with your vehicle’s engine, transmission, and emissions systems.
Common Mercury OBD-II codes include P0171, indicating a system too lean due to faulty oxygen sensors or vacuum leaks. P0300 suggests a misfire issue, potentially caused by faulty spark plugs, ignition coils, or fuel injectors.
Other codes, like P0401, P0700, and U0100, may point to issues with exhaust gas recirculation (EGR), transmission control, and engine control, respectively.
When your Malfunction Indicator Light (MIL) comes on, it’s time to check these codes and address any problems to guarantee your vehicle runs smoothly and meets vehicle emissions standards.
Most Common Mercury OBD-II Trouble Codes
| Code | Description |
|---|---|
| P1000 | System readiness test not complete |
| P1001 | Key-on engine running (KOER) self-test not able to complete |
| P1100 | Mass air flow (MAF) sensor intermittent |
| P1101 | Mass air flow (MAF) sensor out of self-test range |
| P1116 | Engine coolant temperature (ECT) sensor out of self-test range |
| P1117 | Engine coolant temperature (ECT) sensor intermittent |
| P1131 | Lack of HO2S switch – sensor indicates lean |
| P1132 | Lack of HO2S switch – sensor indicates rich |
| P1151 | Lack of HO2S switch – sensor indicates lean |
| P1152 | Lack of HO2S switch – sensor indicates rich |
| P1200 | Injector circuit malfunction |
| P1201 | Injector circuit open – cylinder 1 |
| P1202 | Injector circuit open – cylinder 2 |
| P1203 | Injector circuit open – cylinder 3 |
| P1204 | Injector circuit open – cylinder 4 |
| P1205 | Injector circuit open – cylinder 5 |
| P1206 | Injector circuit open – cylinder 6 |
| P1211 | Injector circuit malfunction – cylinder 1 |
| P1212 | Injector circuit malfunction – cylinder 2 |
| P1213 | Injector circuit malfunction – cylinder 3 |
| P1214 | Injector circuit malfunction – cylinder 4 |
| P1215 | Injector circuit malfunction – cylinder 5 |
| P1216 | Injector circuit malfunction – cylinder 6 |
| P1260 | Theft detected – vehicle immobilized |
| P1270 | Engine RPM or vehicle speed limiter reached |
| P1299 | Cylinder head temperature (CHT) sensor detected engine overheating condition |
| P1309 | Misfire detection monitor malfunction |
| P1336 | Crankshaft position sensor out of self-test range |
| P1351 | Ignition diagnostic monitor (IDM) circuit malfunction |
| P1380 | Variable cam timing (VCT) solenoid A malfunction |
| P1381 | Variable cam timing (VCT) solenoid B malfunction |
| P1400 | Differential pressure feedback EGR (DPFE) sensor circuit malfunction |
| P1401 | Differential pressure feedback EGR (DPFE) sensor circuit range/performance |
| P1405 | Differential pressure feedback EGR (DPFE) sensor upstream hose off or plugged |
| P1406 | Differential pressure feedback EGR (DPFE) sensor downstream hose off or plugged |
| P1443 | Evaporative emission (EVAP) control system – canister purge valve malfunction |
| P1450 | Unable to bleed up fuel tank vacuum |
| P1451 | Evaporative emission (EVAP) control system – excessive vacuum leak detected |
| P1460 | Wide open throttle A/C cutoff relay circuit malfunction |
| P1500 | Vehicle speed sensor (VSS) intermittent |
| P1501 | Vehicle speed sensor (VSS) out of self-test range |
| P1605 | Keep alive memory (KAM) test failure |
| P1650 | Power steering pressure (PSP) switch out of self-test range |
| P1651 | Power steering pressure (PSP) switch input malfunction |
| P1700 | Transmission indeterminate failure |
| P1701 | Transmission control system MIL request |
| P1702 | Transmission control system MIL request – circuit malfunction |
| P1703 | Brake on/off (BOO) switch out of self-test range |
| P1704 | Digital transmission range (DTR) sensor circuit intermittent |
| P1705 | Transmission range sensor (TRS) circuit malfunction |
| P1860 | Torque converter clutch (TCC) PWM solenoid circuit electrical |
