97 xj no start multiple codes high volt,no bus

I've been lurking for awhile on here and almost every issue I,ve ran into I,ve found a answer to until today. To start I have a 97 auto 4.0 government model with 161k. I've never had a real issue until today. I'm experiencing a no start condition with multiple cels. It started right after i spliced in a new connection for the oil press sending unit and changed the oil.

The codes are
p0113-iat high
p0123-tps voltage high
p0118-coolant temp high volt
p1492-ambient battery temp high
p0122-tps high volt
p1694-no bus

I just can't seem to figure it out, the fuel gauge doesn't register, it cranks fine but wont turn over. I checked resistance across all grounds and came up with less than .5 ohms. Battery is new, alternator, crank sensor is a couple moths old(oem), cap, rotor, wires, coil less than 4 months old, fuel pump is about 8 months old. I,m working by myself so I cant check voltage while it's cranking. It's been running great up to this point I just can't for the life of me figure this out, any help would be appreciated.

Raine883 said:

I've been lurking for awhile on here and almost every issue I,ve ran into I,ve found a answer to until today. To start I have a 97 auto 4.0 government model with 161k. I've never had a real issue until today. I'm experiencing a no start condition with multiple cels. It started right after i spliced in a new connection for the oil press sending unit and changed the oil.

The codes are
p0113-iat high
p0123-tps voltage high
p0118-coolant temp high volt
p1492-ambient battery temp high
p0122-tps high volt
p1694-no bus

I just can't seem to figure it out, the fuel gauge doesn't register, it cranks fine but wont turn over. I checked resistance across all grounds and came up with less than .5 ohms. Battery is new, alternator, crank sensor is a couple moths old(oem), cap, rotor, wires, coil less than 4 months old, fuel pump is about 8 months old. I,m working by myself so I cant check voltage while it's cranking. It's been running great up to this point I just can't for the life of me figure this out, any help would be appreciated.

Click to expand...

It sounds like your oil pressure sensor connector wiring is at fault, putting 5 volts in to the sensor ground circuit.

The ground circuit should only have around .010 to .020 volts on it. With 5 volts in that circuit it would show up as high voltage.

The ground circuit connects all those circuit faults you listed + more.

The ground circuit wire is Brown with a Yellow tracer and the 5 volt supply circuit wire is Orange.

You can disconnect the OPS connector and, using a digital voltmeter, measure the voltage at the connector pin cavity with the Brown/Yellow wire.

The Orange wire pin cavity should have 5.0 +/- .5 volts.

Wait...

Just noticed you have a '97.

Does your oil pressure sensor have two pins or three?

With only two pins it's a different story. The OPS is wired similar to the ECT and IAT. The TPS is in the same ground circuit (Brown/Yellow wire).

Oddly enough the ground circuit goes through the clockspring, which connects the cruise control to the ground circuit.

Measure the voltage at the pin cavity with the Brown/Yellow wire and see what you get.

Edit: Here's a pin out of the OPS connector:

First, did you buy genuine Jeeps sensors ? The symptoms strongly suggest a short circuit to the CCD Bus that the 5 volts sensors use to transfer data.

Sidewinder CC said:

Oddly enough the ground circuit goes through the clockspring, which connects the cruise control to the ground circuit.......

Click to expand...

... and to the Throttle Position Sensor (TPS). The first thing to do is unplug the horn relay, or the clock spring. The horn circuit can go bad, and it will short to the clockpsring, then you have 12 volts on the ground lead feeding into the TPS.


P1694 Fault In Companion Module. No CCD/J1850 bus messages received at the power train control module (PCM) from the AisinWarner Transmission Control Module (TCM).

P1694 will set if no CCd bus messages are received from PCM for 20 seconds or invalid messages are received for 20 seconds.

Possible Causes
-Faulty TCM
-CCD Bus (-) circuit open between PCM and TCM.
-CCD Bus (+) circuit open between PCM and TCM.
-Transmission CCD bus wiring damaged.

(Wiring issues or a faulty TCM should be the first P1694 suspects)

The OPS is a 2 pin, oddly enough before installing the new pigtail the two wires were wrapped together with a wire nut(previous owner). My jeep is a base model with no cruise control. The clockspring sound like a good place to check, i've been having a strange clicking noise from the steering wheel and i've had trouble with it making my gages drop in the past, so ill start there.

Raine883 said:

The OPS is a 2 pin, oddly enough before installing the new pigtail the two wires were wrapped together with a wire nut(previous owner). My jeep is a base model with no cruise control. The clockspring sound like a good place to check, i've been having a strange clicking noise from the steering wheel and i've had trouble with it making my gages drop in the past, so ill start there.

Click to expand...

If you don't have cruise control I wouldn't be concerned about that being the problem.

Check the voltage at the pins cavities.

Who knows, if you unhook the OPS connector everything may return to normal.

I'm starting to suspect my ecu is the problem, I pulled all three plugs hit them with some qd cleaner and re connected them. When I turned the ey the gas gauge rose to about where it should be slowly then dropped. Now the p01692 code is gone. I then unhooked all the sensors and checked voltage, all are reading about .5 volts.

The clock spring is easy enough to disconnect, it should be tried. The horn uses the clock spring and it has been posted before that a faulty clock spring will put 12 volts form t he horn circuit to the 5 volts TPS.

ECU failure is the last thing to suspect, but only after a through and logical diagnostics of the more likely and commoon causes for the codes.

If the clock spring is bad will I still have my horn, blinkers, and Odometer? I haven't had a chance to check pressure at the rail but it seems to be getting fuel just no spark.

I un hooked the clock spring and had no change, I guess I'm going to start checking for a short and pull the fuse block to check for corrosion.

Now the dome lights won't turn off, I'm starting to think thing has lost its mind.

Fixed the dome light, I tested every sensor I could get my hands on, I'm reading 5 volts on both sides of everything but the tps I've got 12 to it. to clarify the iat, crank sensor, all of them have voltage on every pin, no ground on any of them.

Thanks for your help, it ended up being the #4 pin on the ecm, it somehow broke inside the plug, looked like a bad factory crimp, I re pinned it and the old girl is back on the road.