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.
DS1 - Check PSOM Resistance
1994 Ford Aerostar AWD V6-245 4.0LSECTION DS1 - Check PSOM Resistance
Continuous Memory Diagnostic Trouble Code (DTC) 29 indicates that during the last 80 warm-up cycles, the Powertrain Control Module (PCM) detected an error in the Programmable Speedometer/Odometer Module (PSOM) output signal. DTC 452 indicates the PCM detected an error in the PSOM output signal during the last 40 warm-up cycles. Possible Causes:
- Damaged Rear Anti-Lock Brake System (RABS).
- Damaged PSOM.
- Damaged harness circuits.
- Damaged PCM.
- Key "OFF".
- Disconnect PCM. Inspect for damaged or pushed out pins, corrosion, loose wires, etc. Service as necessary.
- Install breakout box, leave PCM disconnected.
- Measure resistance between test pin 3 and test pin 6 at the breakout box.
- Is resistance between 21,000 and 55,000 ohms?
Yes -- Go to DS4. DS4 - Check RABS Sensor Resistance
No -- Go to DS2. DS2 - Check Continuity of the Harness Circuit
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.