Chart A1 Continued (2 Of 2)

If "ENGINE CONTROL SYSTEM" (ECS) light is inoperative and code B334 is current, the ECM may not be powering up with key on, may not be receiving full time power from battery, or may be damaged due to electrical overload or water intrusion.

NOTE: Test numbers refer to test numbers on diagnostic chart.

Check for switched ignition power to ECM.
Check for ground to ECM. Pin "A12" and pin "D1" are redundant grounds. If either ground is okay, ECM should be able to operate normally. If both grounds are open, ECM will not power up.
Check for full time memory voltage supply to ECM. Pin "C16" and "B1" are redundant power supplies to ECM. If either power supply is okay, ECM should be able to operate normally.
If power, grounds and connections are okay, be sure to perform CHART C1 - ECM REPLACEMENT CHECK before replacing ECM. The ECM may have been damaged by electrical overload due to a low resistance component.

Fig 1: Flow Chart A1 Schematic, No "Eng Cont Sys" Lt (Code B334 Current)

Fig 2: Flow Chart A1 (2 Of 2), No "Eng Cont Sys" Lt (Code B334 Current)

Fig 3: Flow Chart A1 (2 of 2), No "Eng Cont Sys" Lt (Code B334 Current)