Flashmasters PCM Repairs

Flashmasters PCM Repair — Troubleshooting Guide (SKU Group)

Important: Use this guide if you reinstalled your repaired Flashmasters PCM and the problem is still happening.
Important: Please do not open/disassemble the PCM or force/probe connector pins (terminals can spread and cause new faults).

• Step 1: Confirm you installed the correct PCM
  • Match the PCM part number (and connector style) to what came out of the vehicle.
  • If a different part number was installed, the vehicle may require programming or the PCM may be incorrect.
• Step 2: Battery voltage and connections
  • Fully charge the battery and verify terminals are clean/tight.
  • Check the battery-to-body and engine-to-body grounds for looseness or corrosion.
• Step 3: Fuse + relay checks (both fuse boxes)
  • Check every PCM/ECM/IGN/ASD fuse (under-hood and interior).
  • Swap the ASD/Main relay with a known-good matching relay.
• Step 4: Connector inspection
  • Unplug PCM connectors and inspect for:
    • Bent/pushed pins, corrosion/green buildup, moisture, or loose terminals
  • Re-seat connectors firmly and verify the locking tabs fully engage.
• Step 5: If the issue is crank/no-start
  • Confirm the ASD relay clicks/energizes during crank.
  • Verify the crank sensor and cam sensor connectors are fully seated and wiring isn’t damaged.
  • Confirm fuel pressure and spark while cranking.
• Step 6: If it starts then stalls / intermittent
  • Re-check ASD relay “hold” power (a weak relay or poor fuse/terminal contact can drop power).
  • Inspect harness near the battery/fuse box for rub-through or prior repair spots.
• Step 7: If you have “no communication”
  • Confirm the diagnostic port has power/ground (a dead port can look like a dead PCM).
  • Disconnect aftermarket add-ons (remote start, alarm, stereo taps, trackers) and retry scanning.
  • Check for network/wiring shorts that can block communication.
• Step 8: If warning lights / multiple unrelated codes
  • Focus first on voltage and grounds (low voltage creates many false codes).
  • Clear codes, then re-scan after a short drive to see what returns.
• Step 9: If the issue started after other work
  • Re-check what was touched: fuses/relays, grounds, sensor plugs, harness routing, and any connector left partially seated.
• Step 10: If the problem persists
  • Have a shop perform voltage-drop tests on PCM power and grounds while cranking/running (finds hidden resistance that basic checks miss).