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Oldsmobile 4-Cyl EFI

  1. With engine at normal operating temperature, connect test light from terminal F of ALCL connector to ground. Raise and support drive wheels several inches off ground, start engine and let idle in neutral.
  2. If test light comes on, transmission 3rd gear apply switch is faulty and should be replaced. If test light does not come on, increase vehicle speed to 30 MPH with transmission in "D". If test light remains off, go to step 5). If light comes on, press brake pedal lightly and watch test light.
  3. If test light stays on, brake switch should be adjusted or replaced. If light goes out, increase speed to 45 MPH. If light remains off, TCC system is OK. If light comes on, turn off engine and return key to "ON" position. Probe White ECM connector terminal 2 with a voltmeter while turning one drive wheel with the other wheel on the ground.
  4. Voltage reading should alternate from below 3 to over 10. If not, check speed sensor. If voltage reading is correct, check for low coolant level and/or excessive coolant sensor circuit resistance. If OK, ECM connector or ECM is faulty.
  5. If test light remained off in step 2), check for blown fuse and replace as needed. Disconnect connector at transmission and connect test light between harness connector A and D. With engine off and ignition in "ON" position, observe test light.
  6. If test light comes on, check for ground in wire to ECM circuit 422. If not grounded, replace ECM. If the light does not come on, connect test light from terminal A to ground. If light does not come on, inspect TCC brake switch circuit and repair or adjust as needed.
  7. If test light comes on, ground TCC test point and again connect test light between connector terminals A and D. If test light comes on, check for faulty transmission TCC connections, faulty TCC solenoid and/or 3rd gear apply switch. Replace as needed. If light goes out, repair open in wire from transmission to terminal F of ALCL connector.
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