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1999 Chevy Cavalier Error code PO200 and PO200P (pending?)

 
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jmrec100 jmrec100
Enthusiast | Posts: 477 | Joined: 09/10
Posted: 09/05/10
05:08 PM

I just finished putting in my new - used engine. Getting error codes PO200 and PO200P . Injector problems. Says Injector circuit open. Where do I start? How do I check the "injector circuit"?

I have another set of injectors from another old engine I can install. How do I check them before installing them? Is there a resistance check I can do?  

jmrec100 jmrec100
Enthusiast | Posts: 477 | Joined: 09/10
Posted: 09/05/10
05:43 PM

I am getting the PO200 error codes wich means injectors. I am going to get a noid light and check each injector there. Is there a resistance or another test I can do?

Also, here's the readings I get from my code reader:

Misfire; Ready
Fuel:    Ready
CCM:    Ready
Cat:     Not Ready
HCN:    N/A
Evap:   Not Ready
2Air:     N/A
AC:        N/A
O2S:     Not Ready
HO2S:   Not Ready
EGR:      N/A

the O2S  and HO2S. How do I check that?  And the EVAP? Where's that and what is it?  

waynep7122 waynep7122
Addict | Posts: 4545 | Joined: 08/09
Posted: 09/05/10
07:40 PM

the last time i ran across a P0200.. some of the injectors were not properly plugged into the connector..


Definition of Diagnostic Trouble Code P0200
Category Powertrain
Definition Injector Circuit/Open





this is a chart of sensor data from a normally operating gm car...

do not look at the whole chart.. take it one line at a time..

makes a LOT more sense that way...

Scandata


you are in the OBD2 self tests..  it is the wrong area to be looking in for diagnostics...  

jmrec100 jmrec100
Enthusiast | Posts: 477 | Joined: 09/10
Posted: 09/05/10
08:15 PM

In the wrong area to be looking?  OBD2 self test? Sorry. I'm using the code reader I have.
I read that the injectors should read between 11 to 18 ohms??  Is that right? I have 7 injectors, 4 from my previous motor and 3 from a spare I was given. They all measure about 2.3  to 2.6   Is 11+ right?
I put in a noid light and it light up so the circuit seems to be working. I'll try seating the injectors again. Probably buy a new seal kit for them tomorrow at autozone. Cheap easy and good fix for leaking seals. The motor runs like a lawnmotor.
I started the engine and listened to how it runs. Then shut it off and pulled an injector plug. Started at #4.  Got worse as  pulled injector 4. Reconnected it, then pulled 3. etc...
Ran worse with 2 off. So I figured its 2.  
Im going to run the noid light test again. And report back. How do I test the voltage at the O2 sensor?  

jgate-#002 jgate-#002
Guru | Posts: 953 | Joined: 06/07
Posted: 09/05/10
09:28 PM

The Powertrain Control Module (PCM) has four fuel injector driver circuits, each of which controls a fuel injector. The PCM monitors the current in each driver circuit and is able to control the driver circuit.  This DTC is also set if a fuel injector driver is shorted to voltage. Long term and short term fuel trims that are excessively high or low are a good indication that an injector is malfunctioning
An erratic voltage reading (large fluctuations in voltage that do not stabilize) indicates an intermittent connection within the fuel injector.Resistance Ohms 11.4-12.6  Voltage Specification at 50°F-95°F  5.7-6.6
Since the voltage is supplied to the fuel injector on a single circuit before the fuel injector harness, the malfunction could only be a poor electrical connection or an open in the fuel injector harness. An open before the harness would result in a Cranks But Will Not Run complaint.  
The injectors are controled by the crank sensor perform the crankshaft position system variation learn procedure.

Block the drive wheels and set the vehicle parking brake.
Put the vehicle in Park or Neutral.
Turn all the accessories OFF.
Install a scan tool.
Start and run the engine until it is at normal operating temperature 85°C (185°F).
With the engine still running, enable the Crankshaft Position System Variation Learning Procedure with the scan tool.
Press and hold the brake pedal firmly and raise the engine speed to the specified value, RELEASING the throttle as soon as the engine cuts out.
Verify with the scan tool that the crankshaft variation has been learned.

The evaporative emission (EVAP) control system limits the fuel vapors from escaping into the atmosphere. The EVAP transfers the fuel vapor from the sealed fuel tank to an activated charcoal EVAP canister. The EVAP canister stores the vapors until the engine is able to use the extra fuel vapor.When the engine is able to use the extra fuel vapor, the intake air flow purges the fuel vapor from the carbon element, and then the normal combustion process consumes the fuel vapor.
As for the oxygen sensors, cat, and EVAP not ready how long did you have this engine running? Sometime depending on the PCM it will take a time to go through a PCM relearn proceedure.  

jmrec100 jmrec100
Enthusiast | Posts: 477 | Joined: 09/10
Posted: 09/06/10
01:00 AM

Looks like the PCM Computer. Where's a good place to buy ?  

jmrec100 jmrec100
Enthusiast | Posts: 477 | Joined: 09/10
Posted: 09/06/10
01:52 AM

Strange results.
#1 and #2 fail the noid test. Only a faint dim light for both injectors. #3 and 4 flash like they are supposed to.  Looking at the wiring diagram, it looks like the greyish colored wires are common to all 4 injectors. Now in the diagram, connector points for the NON common contacts for the fuel injectors on the CPM are pt 19 (Black) for #1 injector and pt 20 (Lt grn/Blk) for #2 injector.  

Connector points for the NON common contacts on the CPM are pt 17 (Pnk/Black) for #3 injector and pt 15 (Lt Blu/Blk) for #4 injector.  Looks like separate banks of connections for the PCM. s there a way to check the PCM?

Did a voltage test on the injectors while running. Each had 12.4V across the grey wire with just the key on and NOT running.  and zero on the other non common wires of each injector. Then ran connections of the negative lead of the multimeter  to the positive of the battery. Measured across each connection. Each leg of the injector measured -12.4V across each lead to the posiive of the battery.
Then stripped back the wires on #1 and #3 since believe a problem in #1 and #2 injectors.  #2 and #1 didn't read right. It looks like the PCM. Any ideas?  

waynep7122 waynep7122
Addict | Posts: 4545 | Joined: 08/09
Posted: 09/06/10
07:19 AM

i was thinking about your resistance test on the injectors...  was there a low ohm reading.. that would take more power.. possibly damage the drivers in the pcm... so you might need new injectors and a PCM...


jgate posted this Resistance Ohms 11.4-12.6


feel like opening the computer and checking the solder joints on the circuit board...   i just finished resoldering a 98 vortec pcm.. made it run good again..    not for novices at soldering




have you unplugged the PCM completely... ohmed the harness with the injectors plugged in... to verify the harness  ohms properly...  

jmrec100 jmrec100
Enthusiast | Posts: 477 | Joined: 09/10
Posted: 09/06/10
08:56 AM

I read the ohms in the injectors. I read the books saying should read 11 to 18 ohms. I have set of 4 with the old engine and another set of 3. All read 2.3 to 2.7 ohms. Rather low. I am questioning if the required 11 to 18 ohms is correct. Next step I will check the harnesses. How do you separate out which connector is which. I have a schematic and it shows different contact points. I see two large connectors. I an assuming that the two injectors 1 and 2  are on one connector. Then 3 and 4 are on the other. I don't see any connectors labeled on the PCM.

++++++++++++++++++
UPDATE on INJECTOR Ohms;
Per the dealer, the injectors should read 1.95 to 2.3 ohms to be good.
Even though Haynes book says 11 to 18. The dealer checked several places and verified these. Mine are all good readings !  

jmrec100 jmrec100
Enthusiast | Posts: 477 | Joined: 09/10
Posted: 09/06/10
09:09 AM

jgate:
I just got the engine installed. And running. Has little time on it now. Has not even reached running temp yet so I would agree that the pcm hasn't learned yet. But the #1 and #2 injectors are not lighting up like they should. The noid test light only is very dim, barely lit and does not flash. #3 and #4 noid light test, they are light bright and flash.
Is the 11 ohm plus reading a real number? I have a hard time believing all 7 of my injectors are low. But the 3 extra came from spare engine of 70,000 miles. The 4 from my old engine I just replaced had lots of miles. But all 7 reading low?  

jgate-#002 jgate-#002
Guru | Posts: 953 | Joined: 06/07
Posted: 09/06/10
04:36 PM

Each injector has its own driver,
The control driver for #1 and #2 are on the blue connector C1-75(blk wire) and C1 -76(ltgrn/blk wire)
and the control driver for #3 is on the black connector C2-76 (pink/blk wire)
and the control driver for #4 is on the black connector C2-75 (ltblu/blk wire)
And yes the 11 ohms is defiantly a real number.check you voltage output closer to the PCM. Voltage Specification at 50°F-95°F  5.7-6.6  

jmrec100 jmrec100
Enthusiast | Posts: 477 | Joined: 09/10
Posted: 09/06/10
07:41 PM

Thanks for the info. I went to the yard to look at other injectors. I found different injectors from different cars (Pontiac, Malibu, ) and they all measured 12.4, 12.5 ohms. I did find one cavalier, 1997 with same injectors but mounted in the front - earlier year model.  All 4 measured 2.2, 2.3 like mine. That is what confuses me. Now maybe those were all bad too? All 4 measured consistant with each other but much lower than 12 ohms. The cars were damaged so that leads me to believe the accident is why the cars were there- totaled. Not an engine failure?  Will the cars still run that low? probably run awful.?
While at the yard, I measured one Cavalier between the injectors. The commons are connected (grey wires). When I measured between the other wires, there no connection, This is with their PCM connected. Mine had some connection between the hot sides. Probably a short or scraped wire shorting to each other or ground.  
Im going to ohm out the harness with out the PCM. Any other ideas?
I went and bought another PCM at the yard. If it works, then I know the problem was the PCM. If not, maybe 2 bad PCM's. I wanted to at least try it. I'll need to order new injectors anyway. As was said, low resistance 2.3 ohms may burn out the PCM.  

jmrec100 jmrec100
Enthusiast | Posts: 477 | Joined: 09/10
Posted: 09/06/10
10:22 PM

A little more information but I still have a request. With the PCM disconnected, I check continuity between the wires of the #1 and #2 injectors. I used the wiring diagram in the Haynes book. The grey wires do show continuity like they are supposed to. Should have continuity between all 4 injectors. Now I check continuity between the grey and the other leads of the injectors - Result NO continuity. That's good. It was with the PCM connected . I am trying to test the wires to each individual injector but doesn't seem to match the Haynes Manual. I look at injector 1 and the colored lead (Black) should be at connector point 19 on the PCM connector. Doesn't match. I tried a few points close to where I thing the wire runs and I don't fsee it on the meter. Anyone have which connector point is the right one.

EXAMPLE
injector 1 per Haynes Manual shows the grey wire joining the other injectors and terminating at connector point 8. Can't find it on either one of the two harnesses.

Then injector 1 black wire is shown to connect at connector point 19. Don't see it.

Injector 2:  Lt Grn/Blk  at point 20 - Not There
and Grey joins other injector and joins at  pt 8- Don't see it

Injector 3:  Pink/Bk  at point 17 on a different harness? - Not There and Grey joins other injectors and joins at  pt 8- Don't see it

Injector 4:  Lt Blu/Blk  at point 15 on a different harness? - Not There and Grey joins other joins other injectors ad joins at  pt 8- Don't see it  

jgate-#002 jgate-#002
Guru | Posts: 953 | Joined: 06/07
Posted: 09/07/10
07:00 AM

Drivers are fault protected. If a relay or solenoid is shorted, having very low or zero resistance, or if the control side of the circuit is shorted to voltage, it would allow too much current flow into the PCM. The driver senses this and the output is turned OFF or it's internal resistance increases to limit current flow and protect the PCM and driver.  If the circuit from B+ to the component or the component is open, or the control side of the circuit is shorted to ground, terminal voltage will be low. Either of these conditions is considered to be a driver fault.

For injector driver for #1 you want the blue connector terminal 75..(C1-75)
and for injector driver #2 you want the blue connector terminal 76..(C1-76)Since these drivers get there power from the same circuit in the PCM, I believe your problem is a leaking zener diode.
I you would like , post you email address ( or send me a PM)and i will send you what I have on this PCM..To big to post here>>  

jmrec100 jmrec100
Enthusiast | Posts: 477 | Joined: 09/10
Posted: 09/07/10
05:36 PM

I found out from the dealer specs that my injectors are good. I read in Haynes manual too that they should read 11 to 18 ohms. BUT looking at the dealer specs, Mine are good. The injectors should read between 1.95 to 2.3 ohms.  A big difference. So all my injectors are good. Makes sense because #3 and #4 run fine. Having trouble with #1 and #2.  Looks like a wire or PCM problem.
This is a great forum. And I really appreciate the help I'm getting.  

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