Error Code P1245 is defined as Alternator Load Input Failed Low.

This error code is a generic trouble code, meaning it applies to all vehicles equipped with OBD-II system or vehicles made since 1996 up to present. Specifications, troubleshooting, and repairs, of course, vary from one make and model to another.


The PCM (powertrain control module, also known as ECM or engine control module in other vehicle makes) monitors generator load from the generator or regulator in the form of frequency. The Error Code P1245 means the input is below the specified load for normal operation. This could happen when there are no generator output exits.

Common Symptoms

This code activates the Check Engine light, which is also usually its only symptom.

Possible Causes

Many factors lead to this error code. Some of the most common possible causes include:

  • Defective Alternator/Generator
  • Broken Alternator Belt
  • Open or shorted Alternator/Generator harness
  • Poor electrical connection in Alternator/Generator circuit
  • Damaged PCM (rare)

How to Check

To diagnose for this error code, technicians usually start by checking the alternator/generator for signs of damage and malfunction.

Then, they proceed on checking the alternator belt if it’s still in good running condition.

Next, they check for open or shorted harness of alternator/generator.

Next, they check for any signs of burnt, damaged, or scuffed electrical wirings in the alternator/generator circuit.

How to Fix

Repairs for this error code are easy, but of course, successful repair can only be made possible through a thorough diagnosis of the problem. For the repairs, however, some of the most common fixes are:

  • Repair or replacement of the defective alternator/generator
  • Replacement of broken alternator belt
  • Repair or replacement of open or shorted alternator/generator harness
  • Repair or replacement of the electrical connection in the alternator/generator harness circuit
  • Reprogram or replacement of defective PCM (rare)

PCM damage is usually the last resort if all things fail in diagnosis. It’s quite a rare condition, but can be possible.