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.
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HOMESERVICE MANUALSFORD1991AEROSTAR VAN CARGO EXTENDED, 4.0 X, AWDREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCESYSTEMENGINE CONTROLS - TESTS W/CODES - 4.0LCODE-TO-TEST MENUSKOEO CODE-TO-TEST MENU
1991 Ford Aerostar Van Cargo Extended, 4.0 X, AWD
KOEO Code-To-Test Menu
1991 Ford Aerostar Van Cargo Extended, 4.0 X, AWDSECTION KOEO Code-To-Test Menu
KOEO SELF-TEST - CIRCUIT TEST & STEP MENU
| Code No. | Description | Go To: Test No. (Step No.) |
|---|---|---|
| 15 | Code 15, 511 Or 512 Koeo Or Continuous Memory Code | QB (3) |
| 16 | EDIS Ignition Ignition Diagnostic Monitor (IDM) | NC (2) |
| 19 | Replace Processor | ..... |
| 21 | Temperature Sensor Test (ACT & ECT) | DA (1) |
| 22 | MAP/BP Sensor | DF (1) |
| 23 | Throttle Position Sensor (TPS) | DH (2) |
| 24 | Temperature Sensor Test (ACT & ECT) | DA (1) |
| 26 | MASS Airflow Sensor (MAF) | DC (1) |
| 51 | Temperature Sensor Test (ACT & ECT) | DA (10) |
| 53 | Throttle Position Sensor (TPS) | DH (3) |
| 54 | Temperature Sensor Test (ACT & ECT) | DA (10) |
| 56 | MASS Airflow Sensor (MAF) | DC (20) |
| 57 | Octane Adjust | KP (1) |
| 61 | Temperature Sensor Test (ACT & ECT) | DA (20) |
| 63 | Throttle Position Sensor (TPS) | DH (1O) |
| 64 | Temperature Sensor Test (ACT & ECT) | DA (20) |
| 66 | MASS Airflow Sensor (MAF) | DC (10) |
| 67 | Neutral Drive Input | TA (1) |
| 79 | WAC & A/C Demand Switche | KM (40) |
| 85 | Canister Purge (CANP) | KD (6) |
| 86 | A4LD Transmission | TB (1) |
| 87 | Fuel Pump Circuit (Relay & Inertia Switch) | J (7) |
| 89 | E4OD Automatic Transmission | TC (12) |
| 91 | E4OD Automatic Transmission | TC (12) |
| 92 | E4OD Automatic Transmission | TC (12) |
| 93 | E4OD Automatic Transmission | TC (12) |
| 94 | E4OD Automatic Transmission | TC (12) |
| 95 | Fuel Pump Circuit (Relay & Inertia Switch) | J (20) |
| 96 | Fuel Pump Circuit (Relay & Inertia Switch) | J (30) |
| 97 | E4OD Automatic Transmission | TC (5) |
| 98 | E4OD Automatic Transmission | TC (15) |
| 99 | E4OD Automatic Transmission | TC (15) |
| No Code/Codes Not Listed | ..... | QA (1) |
RENDER: 1.0x
NO RELATED
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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.