Diagnosing issues with your Ford E250 van often begins with understanding the trouble codes your vehicle’s computer system is trying to communicate. These codes, signaled through your check engine light, can pinpoint problems within your engine, transmission, and other systems. While newer vehicles use OBD-II scanners for this purpose, older Ford E250 vans may utilize a different, pre-OBD system. This guide will walk you through how to read trouble codes on your Ford E250 van, covering both methods to ensure you can diagnose your vehicle effectively, regardless of its model year.
Understanding Your Ford E250 Diagnostic System
Before diving into the code retrieval process, it’s important to understand the diagnostic systems at play. Most Ford E250 vans, especially older models, utilize an EEC-IV (Electronic Engine Control) system. This system predates the standardized OBD-II (On-Board Diagnostics II) system that became mandatory in the mid-1990s. While some later E250 models might have OBD-II ports, many still rely on a self-test procedure using the EEC-IV system’s diagnostic connectors. This guide primarily focuses on the EEC-IV system, which is relevant for many E250 vans and doesn’t require a scan tool to access basic trouble codes.
Locating the Self-Test Connectors
The first step is to locate the self-test connectors. These are typically found on the driver’s side inner fender well, often near the firewall or strut tower. Look for a set of connectors, one of which resembles the shape of a house, or a trapezoid. These are the diagnostic connectors you’ll use to initiate the code reading process.
Reading Key On Engine Off (KOEO) Codes
The Key On Engine Off (KOEO) test reads codes stored in the computer’s memory with the engine off.
- Prepare the Vehicle: Ensure your engine is at normal operating temperature before starting. Turn off the engine and locate the self-test connectors.
- Connect the Jumper Wire: Use a jumper wire to connect the designated self-test connectors as shown in the diagram.
- Turn Key to RUN: Turn your ignition key to the RUN position (KOEO – Key On, Engine Off). Do not start the engine.
- Observe the Check Engine Light: Watch the “CHECK ENGINE” or “SERVICE ENGINE SOON” light on your dashboard. The light will begin to flash out codes. If you are using a voltmeter, connect the negative lead to ground (white wire from connector) and the positive lead to the positive battery terminal. The voltmeter needle will sweep to indicate the codes.
- Record KOEO Codes: Count the flashes or voltmeter sweeps. Codes are displayed as a series of short flashes. For example, two quick flashes, a two-second pause, then three quick flashes indicate code 23. Three-digit codes will have an extra two-second pause before the third digit. Record all KOEO codes. There will be a four-second pause between multiple codes.
Reading Continuous Codes
After the KOEO codes are displayed, continuous codes will follow.
- Wait for Continuous Codes: After the last KOEO code, there will be a 6 to 9-second pause, a quick flash, and another 6 to 9-second pause.
- Record Continuous Codes: The “CHECK ENGINE” or “SERVICE ENGINE SOON” light will now flash continuous codes in the same manner as KOEO codes. Record these codes separately and identify them as continuous codes.
- Turn Key Off: Turn the ignition key off and remove the jumper wire after recording all continuous codes.
Reading Engine Running Codes
The engine running test provides codes that appear when the engine is running.
- Warm Up Engine: Start the engine and run it at 2000 RPM for two minutes to warm up the sensors.
- Turn Off and Wait: Turn off the engine and wait for 10 seconds.
- Install Jumper and Start Engine: Install the jumper wire again, start the engine, and let it idle.
- Engine ID Code: Observe the “CHECK ENGINE” light for the engine identification code. It will flash three times for a six-cylinder engine and four times for an eight-cylinder engine.
- Brake and Steering Tests (If Applicable):
- E4OD Transmission: If your E250 has an E4OD transmission, press and release the brake pedal immediately after the ID code to test the brake on/off switch.
- Power Steering Pressure Sensor: If equipped with a power steering pressure sensor (4.9L and 5.0L ’87-’90 and ’93 5.0L without E4OD), turn the steering wheel at least a half turn and return it immediately after the ID code (or after the brake test).
- Wide Open Throttle (WOT) Test (If Indicated): Watch for a single quick flash after the brake/steering tests (or ID code if no tests). If a single flash occurs, quickly floor the gas pedal and release it to perform a Wide Open Throttle test. Note: Only perform the WOT test if indicated by the single flash.
- Record Engine Running Codes: The “CHECK ENGINE” light will now display engine running codes. Record these codes and identify them as engine running codes.
- Turn Off and Remove Jumper: After all engine running codes are displayed, turn off the engine and remove the jumper wire.
Clearing Trouble Codes
After repairing the issue indicated by the trouble codes, you’ll want to clear the codes from the computer’s memory.
- Jumper Wire Method: During the KOEO test, remove the jumper wire before all codes are displayed. This can sometimes clear the codes.
- Battery Disconnect Method: Disconnecting the battery is a more common method. Disconnect the negative battery terminal for about 15-20 minutes. Note: Disconnecting the battery will reset the computer’s memory, including its learned driving style. This may cause a slightly different engine performance until the computer relearns your driving habits.
Important Note: Always clear trouble codes after performing repairs to ensure that only new issues are flagged in the future.
Important Notes and Troubleshooting Tips
- Check Engine Light Bulb: Ensure your “CHECK ENGINE” or “SERVICE ENGINE SOON” light bulb is functioning correctly. A voltmeter is not required if your check engine light is working.
- Voltmeter (Optional): While not necessary if your check engine light works, a voltmeter can be used as an alternative indicator for code flashes.
- Record All Codes: Carefully record all KOEO, continuous, and engine running codes in the order they are displayed.
- Consult a Repair Manual: Once you have the trouble codes, consult a Ford E250 repair manual or online resources to identify the meaning of each code. This will guide you in diagnosing and repairing the underlying issues.
By following these steps, you can effectively read trouble codes on your Ford E250 van using the EEC-IV self-test system. This DIY approach can save you time and money in diagnosing common automotive problems.
