Back to 1998 Mazda B2500

1998 MAZDA B2500

2.5L I4FWDAUTOMATICgas
Repairs0Labor469Torque4906Fluid6DTC640Battery0Maintenance0Recalls0
P1633low severityPowertrain

KAM Voltage Too Low

on 1998 Mazda B2500 2.5L I4 · FWD

What this code means

The PCM has detected that the Keep Alive Memory voltage is too low to maintain stored data. The PCM will lose adaptive values and must relearn when power is restored.

Symptoms

  • Check Engine Light
  • Loss of adaptive fuel trim values
  • Rough idle after restart
  • Transmission relearning shift points

Common causes

  • Discharged battery
  • Corroded battery cables
  • Excessive parasitic drain
  • Blown KAM fuse
  • Faulty PCM power relay

Diagnostic steps

  1. Test battery voltage with key off (should be above 12.4V)
  2. Inspect battery terminals for corrosion
  3. Check KAM fuse
  4. Test for parasitic drain
  5. Check PCM power relay

Repair notes

Clean battery terminals; replace the battery if discharged; repair the KAM power circuit.

Other Powertrain codes on this vehicle

Building an app?
Free API access to all this data — 50 requests/day, no card required.
Get an API key →
Run a shop?
Manage repairs, estimates, and customers with ShopBase — $249/mo, all features included.
Try ShopBase →