Issue: Misfire, O₂ sensor, EVAP leak, catalyst, fuel trim (Ford 2.5/1.5L/2.0L ecoboost).

Symptoms: Rough idle, power loss, flashing = severe misfire, fuel odor, increased emissions.

🔬 Diagnosis (multiple options): ① OBD2 scanner: read codes (P0300, P0420, P1450). ② Check gas cap tightness (common). ③ Monitor live data: fuel trims (>±15% = vacuum leak). ④ Perform smoke test for evap. ⑤ Inspect ignition coils for oil intrusion (2.0L). ⑥ Compression test if misfire persists.

💰 Cost: $90 (diagnosis) – $2,800 (cat)

Issue: Weak battery, failed alternator, corroded terminals, belt slip.

Symptoms: Slow crank, dim dash, “Check Charging System” message, flickering lights.

🔬 Diagnosis: ① Multimeter: engine off 12.4V+, running 13.8-14.8V. ② Load test battery (AutoZone free). ③ Inspect belt & tensioner (1.5L ecoboost known for tensioner failure). ④ Check alternator diodes for AC ripple. ⑤ Perform parasitic draw test (over 50mA = issue).

💰 Cost: $160 (battery) – $850 (alternator)

Issue: Low oil level, faulty sending unit, worn pump, clogged pickup.

Symptoms: Red oil can light, ticking noise, engine hot, possible rattling.

🔬 Diagnosis: ① Immediately check dipstick level & condition. ② Mechanical pressure gauge (min 10psi per 1000rpm). ③ Inspect oil filter and pressure relief valve. ④ For 1.6L/2.0L ecoboost, check chain tensioner (can restrict oil). ⑤ Oil pressure switch test (resistance).

💰 Cost: $55 (switch) – $1,600 (pump/engine)

Issue: Overheating, low coolant, stuck thermostat, water pump failure (common on 1.5L).

Symptoms: Needle in red, steam, loss of heat, “Engine Over Temperature” message.

🔬 Diagnosis: ① Check reservoir level. ② Pressure test cooling system (leaks). ③ Verify radiator fan operation. ④ IR gun at thermostat housing (should open at ~195°F). ⑤ Inspect for white smoke (head gasket). ⑥ Scan for temp sensor reading (ECT).

💰 Cost: $140 (flush) – $1,300 (water pump/thermostat)

Issue: Low brake fluid, parking brake on, brake failure, ABS fault.

Symptoms: Spongy pedal, increased stopping distance, warning light with !.

🔬 Diagnosis: ① Check fluid level & condition (dark = contamination). ② Inspect pads & rotors (min thickness). ③ Look for leaks at calipers, lines, master cylinder. ④ Scan ABS module (codes C1095, C1234). ⑤ Check brake switch operation.

💰 Cost: $100 (fluid flush) – $1,200 (ABS module)

Issue: Wheel speed sensor, tone ring, ABS pump/module, steering angle sensor.

Symptoms: ABS light, traction control off, speedometer dead (rear sensor).

🔬 Diagnosis: ① FORScan or bidirectional tool read ABS codes. ② Compare live wheel speeds (all should match). ③ Check sensor resistance (800-2000Ω). ④ Inspect wiring near wheel well for corrosion. ⑤ Verify tone ring integrity (cracked).

💰 Cost: $180 (sensor) – $1,050 (ABS module)

Issue: Clockspring broken, seat belt pretensioner, crash sensor, passenger occupancy sensor.

Symptoms: Airbag light on, horn/steering wheel controls dead (clockspring).

🔬 Diagnosis: ① SRS scanner (generic OBD2 insufficient). ② Check under-seat yellow connectors. ③ Clockspring continuity test (multimeter). ④ Check for open recalls (Takata). ⑤ Passenger seat weight sensor (common fault).

💰 Cost: $200 (clockspring) – $1,400 (occupancy sensor)

Issue: Low pressure, dead sensor battery, missing sensor, relearn needed.

Symptoms: TPMS light solid or flashing, pressure display shows dashes.

🔬 Diagnosis: ① Inflate to spec, drive 10 min (may reset). ② TPMS tool to trigger sensors (IDs). ③ Check for damaged valve stems. ④ Verify sensor frequency (315MHz). ⑤ Relearn procedure after tire rotation.

💰 Cost: $45 (relearn) – $280 (set of 4 sensors)

Issue: EPS motor, torque sensor, 12V battery low, wiring (rack mounted).

Symptoms: Heavy steering at low speed, “Power Steering Assist Fault” message.

🔬 Diagnosis: ① Check battery voltage (below 12V causes assist drop). ② Scan EPS module for C2005, U3000. ③ Perform torque sensor calibration (IDS). ④ Inspect harness at steering column (chafing). ⑤ Check power steering fuse.

💰 Cost: $400 (torque sensor) – $2,100 (rack assembly)

Issue: Shift solenoid, valve body (6F35 common), TCM, fluid overheat.

Symptoms: Harsh shifts, slipping, “Transmission malfunction” limp mode.

🔬 Diagnosis: ① Scan TCM codes (P07xx, P2700). ② Check fluid level & smell (burnt = overhaul). ③ Perform line pressure test. ④ Inspect valve body for bore wear (6F35). ⑤ Update TCM software (Ford SSM).

💰 Cost: $250 (fluid/filter) – $4,500 (rebuild)

Issue: Throttle body carbon, accelerator pedal sensor, wiring.

Symptoms: Reduced power, “Engine Power Reduced” message, no response.

🔬 Diagnosis: ① Scan for P2100, P2119, P2135. ② Clean throttle body (carbon). ③ Perform throttle adaptation (FORScan). ④ Check pedal position sensor voltage (2 sources). ⑤ Inspect harness for damage.

💰 Cost: $100 (cleaning) – $800 (throttle body)

Issue: Camera blocked, misaligned radar, module fault.

Symptoms: Amber lane icon, “Camera blocked” message, cruise control unavailable.

🔬 Diagnosis: ① Clean windshield area behind mirror. ② Check for aftermarket windshield (calibration required). ③ Scan IPMA/C-CM codes. ④ Perform dynamic calibration (drive straight). ⑤ Inspect front radar alignment.

💰 Cost: $0 (clean) – $1,200 (camera/radar)

Issue: Hybrid battery cooling, inverter, high voltage isolation.

Symptoms: “Stop safely now” warning, reduced power, check hybrid light.

🔬 Diagnosis: ① FORScan hybrid codes (P0AA6, P1A0F). ② Check battery blower filter (under rear seat). ③ Perform isolation test. ④ Inspect wiring for rodent damage (soy-based).

💰 Cost: $60 (filter) – $4,000+ (battery module)

Issue: Brake switch, ABS module communication, steering angle sensor.

Symptoms: “Hill Start Assist Not Available” message, light on.

🔬 Diagnosis: ① Check brake switch adjustment. ② Scan ABS for C1145, C1230. ③ Recalibrate steering angle sensor. ④ Verify battery voltage (low causes glitches).

💰 Cost: $90 (switch) – $600 (ABS module)

Issue: Door latch switch, wiring broken in flex boot, BCM.

Symptoms: Door ajar light with all doors closed, interior light stays on.

🔬 Diagnosis: ① Visually check rubber boot between door and body (broken wires). ② Test latch switch continuity. ③ Use BCM data to see which door is open. ④ Lubricate latches (sometimes stuck).

💰 Cost: $40 (clean) – $350 (latch/wiring)

Issue: Low washer fluid, burnt headlight/taillight.

Symptoms: Amber light with wavy lines, “bulb out” message.

🔬 Diagnosis: ① Top up washer fluid. ② Check exterior lights (turn signals, brake). ③ Scan BCM for bulb outage. ④ Replace faulty bulb (LED units may need module).

💰 Cost: $5 (fluid) – $400 (LED assembly)