1996 LT1 P1371 Low-Resolution Distributor Signal Diagnosis
1996 LT1 P1371 diagnosis separating low-resolution distributor signal wiring and connections from an actual Optispark/distributor fault.
Two distributor timing inputs.
The 1996 LT1 distributor provides high-resolution and low-resolution timing signals. P1371 sets when the PCM sees the high-resolution pulses but does not see the expected low-resolution signal.
P1371 does not authorize immediate Optispark replacement. GM specifically calls for inspection of the low- and high-resolution circuits before component replacement.
- Determine whether the fault is active or intermittent and save failure data.
- Inspect distributor connections and the low-resolution circuit for open, short-to-voltage or short-to-ground conditions.
- If the fault appears only hot, test while the failure is actually present rather than after it cools.
- If distributor service becomes necessary, verify the distributor ventilation system as part of the repair path.
- After repair, reproduce the operating condition that originally set the code/misfire.
Confirm the distributor/ventilation architecture physically installed on the car. Do not assume a decades-old modified car still matches its original configuration simply from model year.
AFTER THE FAILURE IS PROVEN
Use the proven failed branch—not the original symptom—to choose the replacement. Go from diagnosis to the Parts Verdict →