1998 XJ no start - No fuel pressure

[sjx40250]

Having this problem with the Jeep.
Suspect bad fuel pump. - After cranking, check fuel pressure by depressing teh relief valve with only a trickle of gas. No fuel rail pressure. Also checked relay which is good.

Other checks?

Looks like I need to drop the tank and hitch.

 

[Tim_MN]

First, some basic diagnostics are in order.

Have you tested the Crankshaft Position Sensor, the most logical and most common cause for a no-start ? Have you tested the fuel pressure ?

1997-2001 the fuel pump should run/prime for 3-5 seconds when the key is turned to ON. You often can hear that inside the XJ, but can hear it for sure with the gas cap removed and your ear to the fill tube.

Have you jumpered the fuel pump relay ? Have you inspected and tested the fuel pump wiring and wire plugs for damage and corrosion ? Tested the wire continuity for power and ground ?

 

[sjx40250]

Connected power to the fuel pump and it ran.
Checked relay by swapping with others and it is good.
Checked power to the relay with ignition on, slightly less than 12v.
No pressure in the fuel rail.
two codes, 753 and 1694.
PNW vehicle that is extremely clean in terms of corrosion but unplugged and plugged connectors both at the PCM and at the TCM.
installed new CPS.
Starter fluid indicates potential run capability but no fuel, no start.
Cleaned throttle body.
Now the electric fan comes on when ignition is turned on, new.

 

[Tim_MN]

The e-fan and the P0763 suggest a short circuit in the transmission wire harness or TCM wire harness.


If you have a P1694 suspect a faulty Crankshaft Position Sensor (CPS). The CPS must be tested before you proceed.

Inspect and test the CPS wire plug and wire harness for loose/bent/damaged connection pins, corrosion, and damaged wires. Inspect, clean, and tighten firmly the two ground wires at the ignition coil. They also are ground locations for the transmission computer.

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

In the past there have been reports that the Transmission Control Module (TCM) failures and Keyless Entry (RKE) module failures have caused similar symptoms and faults. Note that the RKE module is on the CCD Bus. Try unplugging the RKE module and try unplugging the TCM and see if the NoBus message goes away and all gauges work. If so, replace the TCM or RKE. Engine sensor wire harness/wire plug issues, a faulty CPS, or a faulty TCM should be the first suspects for a P1694.

Read this >> http://www.naxja.org/forum/showthread.php?t=63167


Read this >> https://www.jeepforum.com/forum/f11/...odule-1359085/

When the CPS short circuits the engine computer (PCM) shuts down to prevent damage to itself. As a result, there is no communication (P1694).
Disconnect your crankshaft position sensor then put the ignition key in the on position. If the instrument cluster voltage and fuel gauges start to work once the CPS is disconnected, then you know the CPS or CPS wires are shorted and is the root cause of the codes. You can verify this by testing the CPS and checking continuity and voltage on the CPS wires.

P1694 Diagnostic Procedure
1. Check instrument cluster gauges for proper operation. If fuel gauge and speedometer operate properly, go to next step. If fuel gauge and voltage meter do not operate properly, test the CPS.
2. Turn ignition off. Disconnect Gray PCM harness connector. PCM is located at left front of engine compartment. Disconnect TCM harness connector. Measure resistance of CCD BUS (-) circuit (White/Black wire) between TCM harness connector and Gray PCM harness connector. If resistance is more than 5 ohms, repair open in CCd BUS (-) circuit (White/Black wire). If resistance is 5 ohms or less, go to next step.
4. Measure resistance of CCD BUS (+) circuit (Violet/Brown wire) between TCM harness connector and Gray PCM harness connector. If resistance is more than 5 ohms, repair open in CCd BUS (+) circuit (Violet/Brown wire). If resistance is 5 ohms or less, replace TCM.
5. Conditions necessary to set DTC P1694 are currently not present. Inspect related wiring and harness connectors. See WIRING DIAGRAMS. Repair wiring as necessary. If no problem is found, check for broken, bent, backed-out or corroded wire terminal pins. Check for chafed, pierced or partially broken wires inside insulation. Repair as necessary.

P1694 Jeep Code - No Messages Received From The Powertrain Control Module

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


P0763 Jeep Code - 3-4 Shift Solenoid Circuit Fault

Possible Causes

-Low transmission fluid level
-Dirty transmission fluid
-Faulty 3-4 Shift Solenoid valve 3-4
-Shift Solenoid valve harness or connectors 3-4
-Shift Solenoid valve circuit is open or shorted

 

[sjx40250]

Will check per above.
Notes:
Cps new and checked
No RKE
No fuel gage with or without CPS connected.

No power to the fuel pump at the connector. Tested pump with 12 volt supply and it operated indicator. Is that that there's a connector problem as there is no reading for fuel level?.

 

[sjx40250]

Ioh other than the fuel gauge, all check lights come on one off as usual when in run position.

 

[RCP Phx]

Did you use a genuine Mopar CPS?

 

[sjx40250]

Fuse issue for fuel pump power.. Suspect intermittent CPS as initial no start condition. All gauges functional.

PCM/TCM CCD (+,-) lines less than 1 ohm. TCM on order.

 

[sjx40250]

RCP_Phx thanks for your help!

 

[sjx40250]

RCP_Phx thanks for your help!

But mostly TIM_MN!

 

[sjx40250]

New TCM now with 0700 code.
Reman TCM.

 

[sjx40250]

Solution was a bad solenoid in the valve body. Worked with the TCM.