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.
1999 Mercury Villager BaseFACTORY OEM SERVICE PROCEDURE
Engine Controls - Tests W/Codes
- Introduction
- Self-Diagnostics
- Quick Test
- Additional System Features
- Summary
- Diagnostic Trouble Code (DTC) Identification
- System Tests
- How To Use Tests
- Test A: No Start/Vehicle Will Not Start
- Test B: Pcm Relay
- Test C: Reference Voltage
- Test DA: Temperature Sensor (IAT & ECT)
- Test Db: Map/BARO Sensor
- Test Dc: Mass Airflow (MAF) Sensor
- Test Dg: Knock Sensor (KS)
- Test DH: Throttle Position (TP) Sensor
- Test DP: Vehicle Speed Sensor (VSS)
- Test Dr: Camshaft Position (CMP) Sensor
- Test DS: Crankshaft Position (CKP) Sensor
- Test Ff: Power Steering Pressure (PSP) Switch
- Test H: Fuel Control
- Test HB: Idle Switch
- Test HC: Fuel Delivery System
- Test Hd: Misfire Monitor
- Test He: EGR System
- Test Hf: Catalyst Efficiency Monitor & Exhaust Systems
- Test Hg: PCV System
- Test HU: Air Intake & Throttle Body
- Test HX: Evaporative Emission System
- Test Ja: Ignition - No Spark
- Test JB: Ignition Misfire Under Load
- Test KA: Fuel Pump Relay
- Test KE: Idle Air Control System
- Test KF: Fan Control (FC) Relays
- Test Km: A/C Relay Circuit
- Test MB: Output Test Mode Not Functioning
- Test NB: Malfunction Indicator Light (Mil)
- Test ND: Engine Speed Signal
- Test QA: Unable To Activate Self-Test/Communication Error
- Test Z: Intermittent
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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