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3 CEL codes, where to look

XBoBJ

XBoBJ

NAXJA Forum User
Location
Spencer MASS
Got 3 codes on my 97 xj 4.0 5 speed. My jeep started running crappy and threw a light for 02 sensors. replaced both of them with some from rock auto. CEl went off and on after that. now its running worse then ever, backfiring popping and sputtering. any idea where to look. Grounds?

P0320 - Ignition/Distributor Engine Speed Input Circuit Malfunction
P0132 - O2 Oxygen Sensor Circuit High Voltage (Bank1, Sensor1)
p0138 - 02 sensor circuit high voltage (bank 1 sensor 2)


thanks,
 
Did you change cap/rotor or do anything with your dizzy? Did you disco the neg bat cable and reconnect to let the ECU reset itself?
 
yes, disconected the battery after i replaced all of them. Also threw a fuel pump in last night. negative on the dizzy. ill change that after work. sometimes it runs decent sometimes it runs really bad. the idle has been very jumpy lately though.
 
Does your Jeep have cruise control? Does it still work?

If you have cruise check the fuse for the CC.
 
I would have suspected a short in the wiring harness wires to the O2 sensors, due to the "high voltage" CEL comment. Sounds like something got a hold of the wires (offroad?) and damaged them to me. That is a common problem, low hanging fruit, wires......too close to the exhaust, drive shaft, and road junk.

http://www.naxja.org/forum/showthread.php?t=1012701&highlight=oxygen+sensor+test

If I am roght, it may have damaged other wires well, related to the Dizzy and engine speed sensor.

Year???
 
Always start with the lowest number code.


P0132 JEEP - O2 Sensor Circuit High Bank 1 Sensor 1

Possible causes
- Front Heated Oxygen Sensor Bank 1 wire harness is open or shorted
- Front Heated Oxygen Sensor Bank 1 circuit poor electrical connection
- Faulty Front Heated Oxygen Sensor Bank 1
- Incorrect fuel pressure
- Faulty fuel injectors
- Intake air leaks
- Exhaust gas leaks



P0138 JEEP - O2 sensor 1/2 Circuit high

Possible causes
- Rear Heated Oxygen Sensor Bank 1 wire harness is open or shorted
- Rear Heated Oxygen Sensor Bank 1 circuit poor electrical connection
- Faulty Rear Heated Oxygen Sensor Bank 1
- Incorrect fuel pressure
- Faulty fuel injectors
- Intake air leaks
- Exhaust gas leaks


P0320 (M) No RPM Signal to PCM. Crankshaft Position Sensor CKP signal has not been detected at the PCM.

Inspect the CKP/CPS wires and test the sensor.
 
Make sure the tiny fuses in the PDC aren't blown--one of the three is for the o2 sensors.
 
alright, another new code. I changed the wires and plugs and dizzy rotor. swapped a throttle body with all sensors off a parts engine that i pulled from a running jeep 6-7 months ago. still no dice. looked at the 02 sensor wires and didnt see anything out of the ordinary. going to check the fuse now. heres the new code. after if did the throttle body i reset the codes and the first one that came up was p0138.


p0108 - manifold absolute pressure or barometric pressure circuit high input...
 
I would inspect the engine bay wiring harness around the back of the cyl. head for any damage and then follow it down to the crank sensor. It souns like you may have a break in the harness based on the codes you are getting.
 
Ecomike said:
WHY?
Click to expand...

Because higher number codes can be based on faulty data provided to the ECU by the problem that caused the lower numbered codes. Often the higher number codes will clear themselves when the original problem ( and low number code ) is fixed and the data is correct.
 
XBoBJ said:
p0108 - manifold absolute pressure or barometric pressure circuit high input...
Click to expand...
Since you were working with the throttle body I would make sure the sensors are plugged in on it. Particularity the MAP sensor. I would also make sure that the elbow under the map sensor is lugged in and not clogged or cracked.
 
Which fuse?

After reading what everyone else has said I would have to agree with wiring harness damage. Especially the part Ecomike mentioned for the rear o2 sensor where it goes over the transfer case and rear driveshaft - mine on my 96 caused similar symptoms that resulted in a blown fuse for the ASD relay, which powers damn near everything on the engine management system including the ECU, O2 sensors (there's your code), alternator field coil, fuel injectors, etc.
 
yeah, you have a wiring fault somewhere for sure. Of the short nature, no open circuits here...

Fuse 23? That's the O2 heater fuse, it's in the top row of mini fuses second from the left, right below fog lamp relay number 1. Literally the only thing downstream from it is the O2 sensor heaters. Check to make sure the dark green wire with a white stripe leading to the upstream/downstream is not shorted to anything.

Trouble spots: the one by the rear driveshaft I mentioned, as well as the spot where the upstream O2 sensor goes around the manifolds. If someone has worked on the jeep and improperly routed the cable around the manifold end so it can rest on the #1 exhaust runner it can melt, it's supposed to be routed around the side of the manifold behind the power steering pump to keep it away from that. There's also a clamp on the lower front driver side of the engine block right above the oil pan that holds the wiring so it doesn't rub against the bottom of the header.
 
Shorty said:
I would inspect the engine bay wiring harness around the back of the cyl. head for any damage and then follow it down to the crank sensor. It sounds like you may have a break in the harness based on the codes you are getting.
Click to expand...

Listen to Shorty--he has spoken wisely

X2

LOL!!!!!

Something is shorted, if it blew that fuse. And it may be a mobil part that shorts only when things move around just the right way, like kastein has suggested, especially the O2 sensor wires. If it drew enough current long enough (a more common problem on the Renix O2 wiring) it can melt and short hidden wires deep the harness, setting off other sensor codes.
 
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