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P0200 Code

47K views 4 replies 5 participants last post by  RedSLEd 
#1 ·
PCM enables an injector on intake stroke of each cylinder. Indiviual cylinder fuel control is referred to as Sequential Fuel Injection (SFI). Ignition voltage is supplied directly to fuel injectors. PCM controls each injector by grounding control circuit via an internal switch called a driver. The primary function of the driver is to supply ground for the component being controlled. Each driver or control circuit is equipped with a fault line which is monitored by PCM. When PCM is commanding an injector on, voltage of control circuit should be low. When PCM is commanding injector off, voltage potential of control circuit should be high. DTC will set when PCM detects wrong voltage potential on any injector driver circuit for 5 seconds.

This diagnosis is valid for all SFI engines 1996 and newer (OBD-II).

P0200 Diagnosis (according to Mitchell). I'm making it brief cause I don't have a scanner. The breaks between steps indicate that you will not go to the following step (ie: step 7 is NOT followed by step 8).

Also, I omitted any reference to go to next step. If a condition does not indicate going to a different step, then go to the next step.

1. Verify code by clearing it and see if it comes back.

2. Start engine and, using scan tool, monitor misfire counters.

3. Monitor misfire history counter, if any counter reads more than 0, go to step 16.

4. Check injector fuses. If fuses are open, go to step 8.

5. Turn ignition off. Disconnect injector harness on misfiring cylinder. Turn ignition on, engine off. Using a test light connected to ground and probe connector (I'm not sure which side, but one should light). If test light does not illuminate, go to step 9.

6. Turn ignition off. Connect Injector Test light (J-34730-405)(noid light) to the misfiring injector harness. Start engine. If test light does not flicker go to step 10.

7. Check injector harness connector terminals for poor connections. Replace as necessary. After repairs, go to step 17. If connector terminals are okay, go to step 14.

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8. Turn ignition off. Disconnect all 4 injector harness connectors related to the open injector fuse. Using a test light connected to B+, probe one of the disconnected injector harness connector ignition positive voltage circuit. If the test lamp illuminates, go to step 12.

9. Repair open in injector ignition positive voltage circuit to the isolated injector. After repairs, go to step 17.

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10. Turn ignition off. Disconnect PCM harness connector C1. Check injector driver circuit for an open, short to ground or short to voltage. If injector driver circuit is not open or shorted, go to step 13.

11. Repair injector driver circuit for open, short to ground or short to a voltage. After repair, go to step 17

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12. Repair grounded ignition positive voltage circuit to injectors. After repairs, go to step 17.

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13. Check for poor connection at PCM harness connector. Repair as necessary. Afterrepairs, go to step 17. If connections are okay, go to step 15.

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14. Replace faulty injector(s). After replacing injector(s), go to step 17.

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15. Replace PCM. Program replacement PCM using required equipment.

16. Check for poor connections at injector an PCM terminal. Check for intermittenet short to ground or
open circuit. Repair as necessary. If connections and circuits are okay, see DIAGNOSTIC AIDS.

17. Using scan tool, clear DTC's. Warm engine to normal operation temperature. Select DTC option and SPECIFIC DTC option, the enter this DTC. Operate vehicle within conditons setting this DTC. If scan tool does not indicate that test ran and passed, go to step 2.

18. Using scan tool, select CAPTURE INFO function. If any undiagnosed DTC's are displayed, go to applicable DTC test.

DIAGNOSTIC AIDES:
Check poor connections or proper terminal tension. Check for corrosion, mis-routed harness, rubbed-through wire insulation or a wire broken inside insulation. When injector driver is diabled, an engine misfire will be apparent and a misfire DTC sets. Using FREEZE FRAME and FAILURE RECORDS data may aid in locating an intermittent condition. The FAIL/PASS COUNTER can also help determine how many ignition cycles the diagnostic reported a pass or a fail. Operate vehicle within same FREEZE FRAME conditions such as RPM, load, vehicle speed, temperature, etc. that you observed to isolate when DTC failed.
 
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#3 ·
Okay, thats alot to take in.....just a update:

Iv'e replaced the fuel pump with a Denso unit and also the pressure regulator switch on the rail and the gas gauge now works and it still misses a little but not quite as severe, so I think it's time to take it into the shop and have a professional look at it. I will keep you guys posted with the outcome and thanks for all your help!
 
#5 ·
@robmick71 That was 12 years ago. I wouldn't expect a response.
 
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