Diagnostic Aids

DTC P0748 may set under low voltage conditions caused by high electrical system demands.

Inspect wiring for poor connections at PCM and at transmission 20-pin in-line harness connector. Check for bent, backed out, deformed or damaged terminals. Check for weak terminal tension. Check for chafed wires that could short to bare metal or other wiring. Check for broken wire inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value changes.