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Engine died while driving and won't start back up. Pulling code 42.

3K views 56 replies 6 participants last post by  rleff34 
#1 · (Edited)
93 YJ Engine died and won't start. No Start and Code 42.

The jeep has been driving fine, last night I cranked it up to leave Sonic, got half way around the parking lot/drive thru in 2nd gear feathering the gas and the engine just died. The starter engages, but it doesn't start up. OBD pulling code 42 which means ASD relay or fuel pump relay, to my understanding. (fuel guage reads.) Turning the key on I can hear what I think is the fuel pump turning on, so that could eliminate the fuel pump relay from causing the issue, am I correct? I have tried swapping both the ASD and fuel pump relays with the horn relay with no luck. I'm not sure where to proceed from here. Any help is much appreciated! :confused:
 
#2 ·
You need a meter to read some voltages. Make sure you are hearing the fuel pump kick on. Do you get the check engine light? For giggles jumper across the asd relay from 30/87 in the relay socket(Side of the relay show the numbers) with a short piece of wire and see if it starts.
 
#9 ·
I'm waiting on rain to pass so I can push my jeep off the street and into my driveway for further testing.. but I was doing some testing as well as reading another post that you replied, and I have 12v in both the fuel pump relay and asd relay on pin 30 and you mentioned something about backfeeding? I will report back after I'm able to finish testing the ecm wiring harness. Damn wiper fluid reservoir.
 
#10 ·
#15 ·
rleff34 said:
Meter on ohms from pin 11 to battery ground terminal (disconnected) correct? I'm not very good at wiring.. but pin 11 and 12 read 0.0 when doing that but I'm not sure if I'm doing it right..
I believe you check pins 11 and 12 with pins 3 and 9...
 
#18 ·
No. It's not the crank. Measure the voltage in the ASD relay from pin 85 ground and 86 switched ignition feed with the key on.
 
#21 ·
I can't see it in the pic. I will take a look in a few. Measure the relay again and this time do it with ground on the battery to both 85 and 86.
 
#23 ·
Did you remove the relay to measure it? You will need to disconnect the battery and measure the resistance from 85 to pin 51 on the ecu connector.
 
#24 ·
Yes I did that was with the relay out, key on, 12v from asd relay terminals 85 and 86 when grounded to the battery.
With ohms on 200 (lowest setting on my meter) I was getting a 00.5 reading from pin 51 of ecu to terminal 85 of asd relay. (battery disconnected)
 
#34 ·
Que89YJ said:
You said you had power at the coil when I asked.
I'm sorry, I misread your question. I'm very stressed.
I never tested the coil for power, you forget I'm a noob at all of this, still learning. Is there an easy way to test asd power to the three things listed? I'd assume it isn't getting power because it comes from the asd (which is why I didn't test it already.
 
#36 ·
You are almost there. The asd feedback to the ecu is not there. The same line is the output to the coil, alternator, and the injectors. You can read the resistance from the relay socket pin 87 to each of the items listed. Voltage is a quick check. The wire should be green with an orange trace. We are trying to determine where the harness opened up at. You've done great so far and you're close.
 
#37 ·
Que89YJ said:
You are almost there. The asd feedback to the ecu is not there. The same line is the output to the coil, alternator, and the injectors. You can read the resistance from the relay socket pin 87 to each of the items listed. Voltage is a quick check. The wire should be green with an orange trace. We are trying to determine where the harness opened up at. You've done great so far and you're close.
I'll check into it around 3:30 (central time) when I get home. Thanks
 
#38 ·
Que89YJ said:
You are almost there. The asd feedback to the ecu is not there. The same line is the output to the coil, alternator, and the injectors. You can read the resistance from the relay socket pin 87 to each of the items listed. Voltage is a quick check. The wire should be green with an orange trace. We are trying to determine where the harness opened up at. You've done great so far and you're close.
not sure how I missed this one.
 

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