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"my chipped ECU doesn't work! Help!"

When you say "it doesn't work," what do you mean?

There are a couple of common problems encountered when chipping ECUs:

  • Sometimes the CEL will come on and there will be a pattern of flashes indicating an error code present. See Checking Error Codes.
  • Sometimes the CEL will come on and just stay on continuously. Attempts to jump the service check connector to check for code blinks fail. See Troubleshooting Solid CEL.
  • Sometimes the CEL is not on, but the car still runs horribly. See Troubleshooting Operation?


  • First of all, make sure your battery isn't dead, Then make sure that when you turn the key to the on position(without starting) that the CEL comes on, if not, check the fuses.
  • Next check if the ECU has power and ground by measuring for +5V at the TPS or the MAP sensor, if you still get nothing you may have a faulty PGM-FI main relay which is located under the dash above the hood release and it has a brown connector with 7 wires coming out.

The PGMFI relay is basically two relays in one box, when you turn the key to the on position, one relay supplies +12v to the ecu, injectors, IACV, IABs, etc., and once the ecu has power it supplies the other relay with a ground signal which in turn supplies +12v to the fuel pump which you should hear for about 2 seconds after you turn the key on.

Checking the pin fit of the connector terminals could determine a poor connection to the harness. Use a suitable terminal pin to check haness terminal sockets for a snug fit. A loose fit can cause poor connections and problems.

If all else fails, visit the forums.

This is a work in progress - please feel free to add your thoughts and experiences.

Parents: P75 > Web Home Revision: r1.6 - 01 Feb 2012 - 22:18 GMT - riverrunner06 { Edit | Attach | History | More }
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