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Another fuel gauge issue...

I'm curious if 98 and older had 5v signal down to pin 3... Regardless, I'm on my way too pickup a BOSCH 67658 pump 2hrs away. This way, I have a KNOWN GOOD pump assembly to test with. I'll continue to update.
 
VAcherokee said:
I'm curious if 98 and older had 5v signal down to pin 3... Regardless, I'm on my way too pickup a BOSCH 67658 pump 2hrs away. This way, I have a KNOWN GOOD pump assembly to test with. I'll continue to update.
Click to expand...

I think the factory manuals were revised in 2000 - 2001 to include other information from other sets and re-edited to include other details in the main factory service manual.

FSMs usually come in sets where the main service manual (FSM) is only one part and may refer to another manual from the set.

The 98 XJ factory service manual doesn't include the 12 volt input driver information for the fuel gauge sending unit.

The 98 XJ service manual shows .. (essentially the same as the 99)
.
FUEL GAUGE SENDING UNIT
The fuel gauge sending unit (fuel level sensor) is attached to the side of the fuel pump module. The sending unit consists of a float, an arm, and a variable resistor (track). The resistor track is used to send electrical signals to the Powertrain Control Module (PCM) for fuel gauge operation and for OBD II emission requirements.

For fuel gauge operation: As fuel level increases, the float and arm move up. This decreases the sending unit resistance, causing the fuel gauge to read full. As fuel level decreases, the float and arm move down. This increases the sending unit resistance causing the fuel gauge to read empty.

After this fuel level signal is sent to the PCM, the PCM will transmit the data across the CCD bus circuits to the instrument panel. Here it is translated into the appropriate fuel gauge level reading.

For OBD II emission monitor requirements: A voltage signal is sent from the resistor track on the sending unit to the PCM to indicate fuel level. The purpose of this feature is to prevent the OBD II system from recording/setting false misfire and fuel system monitor trouble codes. The feature is activated if the fuel level in the tank is less than approximately 15 percent of its rated capacity. If equipped with a Leak Detection Pump (EVAP system monitor), this feature will also be activated if the fuel level in the tank is more than approximately 85 percent of its rated capacity.

In 2000 it appears the 2000 XJ FSM was revised to include other information that was originally in other manuals from the complete set of manuals.

If there was an actual difference in operations .. I would think the fuel pump assembly would have been revised in 2000 - 2001 using a different part number.
 
Last edited:
Sidewinder CC said:
I'll bet the 1997-1998 Cherokee Body Diagnostics Procedures Manual gives the details.

VAcherokee,

Why don't you buy one of these manuals and tell us what it says...Only $22.00.

http://www.ebay.com/itm/1997-1998-J...ture&hash=item1c1c12d5aa&vxp=mtr#ht_726wt_679
Click to expand...

Sounds like a good idea or perhaps a 2000 / 2001 manual ..

Your link is for a paper manual, there is a cd version for around $32.11 with shipping.

I have other paper automotive manuals sitting around and collecting dust ... usually become worn, dirty & smudged after a while of use. In some ways the CD version of the manuals are easier to work with.
 
Bosch pump in hand. I plugged it into the body harness and tested all the major increments... Gauge responded to the corresponding locations. I'm going to install it and add fuel in 5gal increments. I'll keep ya'll posted.

Sidewinder CC, I might just do that, thanks for the link!
 
According to ALLDATAPRO (had a friend look into it)

The diagnostic procedure for P0460 / P0462 (Fuel level no change / fuel level sending unit low voltage) BOTH show a problem if the voltage to pin 4 is ABOVE 4.7v. With that said, I'd have to assume 97/98 Cherokee's are supposed to have 5v at pin 3 coming from c26 (PCM -> Fuel Module). I was told and from what I'm reading in the email I received, there was no DEFINITE answer to the 5v 12v debate between 99 and up Cherokee's... simple logic and common sense suggest that if pin 4 shall sweet a DTC above 4.7v that the supplied voltage wouldn't be much higher. If I can confirm this at some point, I WILL post it!

*I just looked up a 2000 Cherokee. All 3 codes for Fuel sending unit P0460, 462, 463 All reference voltage above 9.4v! The 98 down MUST be ~5v at pin 3 and 99 up ~12v.
 
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PROBLEM SOLVED! FAULTY AIRTEX ASSEMBLY

Just completed the fuel pump module assembly (BOSCH 67658 @ NAPA AUTO PARTS FOR $300).

I completely emptied the fuel tank and installed the tank up into the Cherokee. I plugged in the connector, turned the key to RUN and the gauge read E and a few seconds later, warning light came on for low level! I then added 2.5 gallons and turned the key to RUN, gauge read 1/8 no fuel light! Poured in the remaining 2.5 gallons and repeated key RUN, 1/4 tank!! My tank now has EXACTLY 10 gallons in it and the picture says it all!

I hope this thread can be used by others that need EXACT SPECIFICATIONS, because honestly, SidewinderCC & Wsxjeep make this happen! Although I didn't have a problem other than an OEM sending unit that failed followed by an AIRTEX assembly that was utter CRAP and sent me on a wild goose chase that left me wiser and a ton more familiar with my XJ.

Gentlemen, I thank you! !!!1

10257505886_02a084ce75.jpg
 
Last edited:
Re: PROBLEM SOLVED! FAULTY AIRTEX ASSEMBLY

VAcherokee said:
Just completed the fuel pump module assembly (BOSCH 67658 @ NAPA AUTO PARTS FOR $300).

I completely emptied the fuel tank and installed the tank up into the Cherokee. I plugged in the connector, turned the key to RUN and the gauge read E and a few seconds later, warning light came on for low level! I then added 2.5 gallons and turned the key to RUN, gauge read 1/8 no fuel light! Poured in the remaining 2.5 gallons and repeated key RUN, 1/4 tank!! My tank now has EXACTLY 10 gallons in it and the picture says it all!

I hope this thread can be used by others that need EXACT SPECIFICATIONS, because honestly, SidewinderCC & Wsxjeep make this happen! Although I didn't have a problem other than an OEM sending unit that failed followed by an AIRTEX assembly that was utter CRAP and sent me on a wild goose chase that left me wiser and a ton more familiar with my XJ.

Gentlemen, I thank you! !!!1

10257505886_02a084ce75.jpg
Click to expand...

Good work.

Keep an eye on your voltmeter for pending generator faults.

:)
 
Hi, I know this is an older thread, but damn near the best one I've found on this issue. So, at any point did you have a Carter pump in there? I hope my sending level is OK after I put my tank back in with it tonight.
 
Guys I have similar issue.
Could it be related to the fact that a Cluster from a 16gl XJ was put into a 20gl XJ? Just curious if the sending unit or gauge differs from the 16 to the 20 GL thanks.
 
01bluXJ said:
Guys I have similar issue.
Could it be related to the fact that a Cluster from a 16gl XJ was put into a 20gl XJ? Just curious if the sending unit or gauge differs from the 16 to the 20 GL thanks.
Click to expand...

Do this actuator test and see if the fuel quantity indication and low fuel quantity indicator lamp are accurate. The low fuel quantity lamp should come on at about 1/8 tank.

Inst%20Cluster%20Actuator%20Test%20Instructions.jpg

INST%20CLUSTER%20ACTUATOR%20TEST%20CHART.jpg
 
Thanks for the speedy resonance. Did actuator test last night, gauges passed testing. Just thought I would rule out any tank/sender/gauge compatibility before more diagnostics.
 
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