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Ford Taurus P0538 Fault: EVAP Temperature Sensor Wiring Issue Diagnosis

Model: Ford Taurus Fault Code: P0538 Posted: 2020-05-25 04:00

Hello AutoJoe, I'm following up on my Ford Taurus P0538 diagnostic issue related to the EVAP temperature sensor. The gray/red wire connects from the C140 connector (42-pin male under hood) to pin 24, then continues to PCM pin 91. The tan/orange wire is the one in question. I traced it back to the same C140 connector at pin 11 — this connection ends there with no further path. Additionally, the female side of the C140 connector appears unconnected (not pinned out). This suggests a potential wiring or harness issue, possibly due to an engine swap that may have resulted in mismatched or missing connections. Any insight into how to properly diagnose or repair this would be greatly appreciated.

Related fault codes

P0538

Comments (2)

Anonymous 2020-05-25 05:51

Hey AutoJoe — I successfully fixed the A/C function on my Ford Taurus with P0538 code. After investigating, it appears that a previous engine swap likely involved swapping the entire wire harness without proper reconfiguration. I resolved this by jumping a wire from C140 connector pin 11 directly to PCM pin 66 — after which the A/C system engaged normally.

Anonymous 2020-05-25 08:39

That's excellent news! Thanks for sharing. I've noticed inconsistencies in repair databases like Mitchell or Alldata regarding wiring diagrams — they sometimes list components without clearly indicating connections to the PCM. This case highlights that a simple engine swap can introduce major wiring mismatches, especially with EVAP and climate control systems. Glad you found a practical fix.