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  #13  
Old 05-10-2011, 04:58 PM
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Re: Multiple engine codes

ASD has power to 2 sockets, o2 relay socket has no power to any socket (ignition On , not running)
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  #14  
Old 05-10-2011, 05:45 PM
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Re: Multiple engine codes

There should be power on 86 and 30 of the ASD relay. The O2 relay has no power, since the ASD relay cuts off after 1.8 sec. with ignition on and engine off. Point 86 is the 12V supply for the relay and point 30 is the 12V which the relay will switch.
So what happens with the power to the ASD relay (point 86) with the engine running? If the relay starts clicking, or there is a supply problem, or there is a ground problem. Point 86 is the 12 V supply for the relay, point 85 is going to the PCM (and the PCM will switch it to ground to activate the ASD relay). So when the ASD starts clicking, you need to find out first if the 12V is still there or that it is intermittent. But because both the ASD and fuel pump relay use the same supply and both have a DTC stored for open or shorted, probably your problem lies somewhere in the supply.
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  #15  
Old 05-13-2011, 01:50 PM
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Re: Multiple engine codes

Quote:
Originally Posted by Frango100 View Post
There should be power on 86 and 30 of the ASD relay. The O2 relay has no power, since the ASD relay cuts off after 1.8 sec. with ignition on and engine off. Point 86 is the 12V supply for the relay and point 30 is the 12V which the relay will switch.
So what happens with the power to the ASD relay (point 86) with the engine running? If the relay starts clicking, or there is a supply problem, or there is a ground problem. Point 86 is the 12 V supply for the relay, point 85 is going to the PCM (and the PCM will switch it to ground to activate the ASD relay). So when the ASD starts clicking, you need to find out first if the 12V is still there or that it is intermittent. But because both the ASD and fuel pump relay use the same supply and both have a DTC stored for open or shorted, probably your problem lies somewhere in the supply.
Started vehicle and when ASD started clicking the 30 and 86 pins measured 14 volts. The 87 pin was intermittent (test light blinking). put in a bypass wire in the relay from 30 to 87, still clicking but engine running smooth. Seems to indicate bad relay, I swapped relays and no change. Could I have 2 bad relays? some codes disappeared. guess i'll pick up a new relay and see what happens.
Thanks for the help, Glen
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Old 05-13-2011, 03:20 PM
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Re: Multiple engine codes

87 is the switched side of the relay, so if the relay is clicking, this power should be fluctuating as well. Connecting 87 with 30 just ruled out the relay and you could see it in a smoother running engine. It would be strange if the other relay would have the same problem, but its worth a try. Which are the codes you still have left?
But if a new relay will not help, there could be a problem with the wire from the ASD relay point 85 to the PCM point 3 from connector C3. Or it is the PCM itself which opens and closes the ground path rapidly. One of the inputs the PCM uses to activate the ASD relay, is the crankshaft position sensor. This could also be the problem.
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  #17  
Old 05-13-2011, 04:11 PM
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Re: Multiple engine codes

remaining codes after 10km run P0136, 1282 and 1388, all on ASD circuits. Is there any point in checking A142 circuit ? How much voltage should be on pin 85? My gut feeling is that it's the PCM. Had to order relay won't get until Monday I'll check K51 weather permitting, calling for rain next couple of days.
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Old 05-13-2011, 09:32 PM
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Re: Multiple engine codes

That is strange that you keep the DTC for fuel pump circuit open or shorted as well. Did you feel on the fuel pump relay as well to see if it vibrates?
Measuring the A142 circuit will not help, because it has nothing to do with the switching of the ASD relay. Pin 85 on the ASD relay should measure 12V with ignition on and engine off and 0V with engine on. But most probably its fluctuating together with the vibrating relay. Measuring the K51 circuit makes more sense, since that is in the ground circuit of the ASD relay. Strange also that the problem only occurs after the engine is warmed up and not from the beginning. Did you check the wire bundels in the engine compartment for chaving signs?
I would also remove/clean/inspect/reconnect the connectors on the PCM, to rule out any dirty/corroded pin.
Also try to find the PCM ground wires (Z81 and Z82) and see if their ground is ok.
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  #19  
Old 05-14-2011, 07:18 AM
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Re: Multiple engine codes

Fuel pump relay is not vibrating. Pin 85 measures 12v with ignition on not running, measures 0.9v engine running no clicking, and measures 0.9v to 3.0v engine running clicking.
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Old 05-14-2011, 11:36 AM
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Re: Multiple engine codes

The results you found are quite as expected. Only the 0.9 V is some loss down the ASD relay, could be a resistance due to dirty pins on PCM. So did you measure the K51 circuit continuity? You have to wiggle a bit with the cable loom to see if there is not an internally broken wire.
And did you check the PCM connectors?
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  #21  
Old 05-15-2011, 09:55 AM
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Re: Multiple engine codes

K51 circuit continuity 0.3 ohms. Resistance k51 circuit (PDC) to ground 0.0 ohms ( I assume I measured this correctly K51 pin slot in PDC to gound on engine/body, ASD relay removed). PCM connector looks very clean and wiggled wires no change. The thing that really puzzles me is that it occurs after the engine has been running for 5 to 15 minuutes and when you shot the engine off and restart it right away the engine runs fine for another few minutes before the clicking starts again.
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Old 05-15-2011, 07:17 PM
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Re: Multiple engine codes

Unfortunately it looks more and more that the PCM is causing this problem. Did you try to wiggle the wire bundels the moment the problem is there? Searching the net i found more related problems, some solved by cleaning the PCM connectors and others by changing the PCM. Just put "jeep ASD relay chatter" in a search engine and you will find many hits. You are sure as well that the Z81/Z82 ground points are ok? (from the PCM to ground) Is there any way you can get your hands on a PCM for a test? Can you get one cheap from a junk yard?
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  #23  
Old 05-15-2011, 07:58 PM
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Re: Multiple engine codes

yes wiggled wires and connectors as soon as it started clicking. Could only see one ground wire from PCM to engine, the other one must be in behind, will take apart tomorrow. I'll ck out the junk yards as well, not likely to find one. Probably pick up some contact cleaner as well. Can I do additional damage if I drive around using the 30/87 pin bypass other than frying the PCM?
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Old 05-15-2011, 09:49 PM
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Re: Multiple engine codes

In fact the ASD relay is used to supply the 12V to the injectors and ignition coils and also to the O2 sensor heaters. The PCM regulates the ground signal to pulse the injectors and the ignition. When you jumper 30/87 on the ASD relay, you will keep constant power from the battery to the injectors/coils/O2heaters and PCM.
As long as you disconnect it when you stop the engine, i donīt think that you will fry anything. It is the normal position with the engine on.
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