Back to 1998 Mazda B2500

1998 MAZDA B2500

2.5L I4FWDAUTOMATICgas
Repairs0Labor469Torque4906Fluid6DTC640Battery0Maintenance0Recalls0
P1345critical severityPowertrain

No CMP or SGC Signal

on 1998 Mazda B2500 2.5L I4 · FWD

What this code means

The PCM is not receiving a Camshaft Position sensor or Signal Generator C signal. Without this signal, the PCM cannot determine camshaft position for sequential fuel injection and ignition timing, resulting in a no-start or severe running condition.

Symptoms

  • Engine cranks but will not start
  • Engine runs very rough if it starts
  • Check Engine Light
  • Backfiring

Common causes

  • Faulty CMP sensor
  • Damaged CMP sensor wiring
  • CMP sensor connector disconnected
  • Damaged reluctor ring
  • Timing belt or chain failure affecting cam signal

Diagnostic steps

  1. Check for CMP sensor signal on scan tool during cranking
  2. Inspect CMP sensor connector and wiring
  3. Test CMP sensor resistance
  4. Check CMP sensor air gap
  5. Verify timing belt or chain condition

Repair notes

Replace the CMP sensor if it is not producing a signal; check timing belt or chain condition.

Other Powertrain codes on this vehicle

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