Jeep Garage  - Jeep Forum banner

1 - 11 of 11 Posts

·
Registered
2014 Limited
Joined
·
296 Posts
The 99 and 2000 model years are the same tranny. You may have mistaken the 545RFE which is still the same tranny.
The 45RFE and 545RFE automatic transmission in the WJ was notable. It included three planetary gear sets rather than the two normally used in a four-speed automatic. This gave it six theoretical speeds, and it would have been the first six-speed transmission ever produced in volume, but it was programmed to only use five of these ratios. Four were used for upshifts, with a different second gear for downshifts. Although five of the six ratios were used, Chrysler decided to call it a "4-speed automatic". In 2001, the programming was changed to make use of all six ratios. Rather than have six forward gears, the transmission was programmed to act as a five-speed with the alternate second gear for downshifts. The RPM at 70 miles per hour (110 km/h) on a 545RFE is 2000 rpm, 200 rpm less than the 45RFE programming. 1999 and 2000 model year WJ owners can have their 45RFE transmission's programming flashed to enable the extra gear as both transmissions are physically the same. The 42RE 4-speed automatic remained the transmission for the Inline 6 engine. It had slight changes from the previous model Grand Cherokee.

The big differences between 1999/2000 and 2001 is the heater wiring for the upstream O2 sensors, and the A/C.

Note California emissions version. Apparently there was a federal and a California version for 1999 and 2000, difference for California being 4 O2 sensors, 2 mini cats and a main cat, with the sensors before and after the mini cats. Federal version apparently just had one cat and 2 sensors, one before and one after. 2001 and later are all the same, like the 1999/2000 California version (4 sensors, 3 cats) with differences in wiring.

The big difference is that on 1999/2000 the PCM pulls a relay closed and provides power to the upstream O2 sensor heaters through that just like what it does for the downstream sensors. 2001 and later, probably because they wanted to be able to sense an O2 sensor heater open, has power provided to the upstream sensors via the ASD relay, and the PCM provides ground for them directly and individually when it wants to run them. No ~12v sensed at the PCM pins would trigger a trouble code for O2 sensor heater malfunction.
 

·
Registered
1999 Jeep Grand Cherokee Limited 4.7
Joined
·
6 Posts
Discussion Starter #3
Thanks MacDaddy for clearing that up for me. That makes sense to me now. Do you have any idea what that additional connector (pictured with red tape) may be used for or is it just a connector for other models? Thanks again for helping me out on this.
 

·
Registered
2014 Limited
Joined
·
296 Posts
Thanks MacDaddy for clearing that up for me. That makes sense to me now. Do you have any idea what that additional connector (pictured with red tape) may be used for or is it just a connector for other models? Thanks again for helping me out on this.
Did you pull the harness or did you get it used from a parts supplier. I would need to know where the plug is in relation to your old harness, meaning what area the aforementioned plug sits in relation to your old harness. The picture is good but I need some direction as to input location of the female plugs might be one from a 4.7 HO, or a 4.7 Limited or Laredo and they have some major differences an Ie: If an Overland WJ has a 4.7 with the select trac, which most 4.7’s had Quadra trac or Quadra drive and with that there lays your possible differences for the harness.
 

·
Registered
1999 Jeep Grand Cherokee Limited 4.7
Joined
·
6 Posts
Discussion Starter #5
Did you pull the harness or did you get it used from a parts supplier. I would need to know where the plug is in relation to your old harness, meaning what area the aforementioned plug sits in relation to your old harness. The picture is good but I need some direction as to input location of the female plugs might be one from a 4.7 HO, or a 4.7 Limited or Laredo and they have some major differences an Ie: If an Overland WJ has a 4.7 with the select trac, which most 4.7’s had Quadra trac or Quadra drive and with that there lays your possible differences for the harness.
These harnesses have been pulled from my two Jeeps. The harness with the additional plug came from my 2000 Grand Jeep Cherokee Limited with a 4.7 and a Quadra Trac II (right harness in photo) VIN # 1J4GW58NXYC210250 opposed to the harness from my 1999 Grand Jeep Cherokee Limited with a 4.7 Quadra Drive (left harness in photo), VIN # 1J4GW68N9XC550011. Both are non-HO. The harness plugs into the TCM.
 

Attachments

·
Registered
2014 Limited
Joined
·
296 Posts
These harnesses have been pulled from my two Jeeps. The harness with the additional plug came from my 2000 Grand Jeep Cherokee Limited with a 4.7 and a Quadra Trac II (right harness in photo) VIN # 1J4GW58NXYC210250 opposed to the harness from my 1999 Grand Jeep Cherokee Limited with a 4.7 Quadra Drive (left harness in photo), VIN # 1J4GW68N9XC550011. Both are non-HO. The harness plugs into the TCM.
Take another shot of the inside of the plug so I can see the pin out design It obvious the plug that comes from the harness plug in to the the single double pinned male/connector and I need a look at the end of the single plug with the grey pin out area so I can count the connectors pins they tell you what they power. If you noticed the connector pin outs are color coded and that’ll tell you what they power.
 

·
Registered
1999 Jeep Grand Cherokee Limited 4.7
Joined
·
6 Posts
Discussion Starter #7
Take another shot of the inside of the plug so I can see the pin out design It obvious the plug that comes from the harness plug in to the the single double pinned male/connector and I need a look at the end of the single plug with the grey pin out area so I can count the connectors pins they tell you what they power. If you noticed the connector pin outs are color coded and that’ll tell you what they power.
Thanks for taking the time to help. I hope I got the pics you need. I did pin out the plug in question out to a 14 pin plug, so I added pics of that plug as well. The wire colors are BK & BK/RD.
232071
232072


The following pics is of an insert of some sort that plugs into connector.

232073

232074


One end of the insert/adaptor?

232075



Other end that I'm not sure where it plugged into

232076


And the plug where the connector in question pins out to.

232078


232079


232080
 

·
Registered
1999 Jeep Grand Cherokee Limited 4.7
Joined
·
6 Posts
Discussion Starter #8
The 14 pin plug on the 1999 harness is missing the BK/RD pin. As I stated earlier, I will be replacing all electronics of the 1999 with the 2000 harness and electronics.
 

·
Registered
2014 Limited
Joined
·
296 Posts
The 14 pin plug on the 1999 harness is missing the BK/RD pin. As I stated earlier, I will be replacing all electronics of the 1999 with the 2000 harness and electronics.
I’m thinking it’s an output speed sensor connector. Let me know How it works out for you.
 

·
Registered
1999 Jeep Grand Cherokee Limited 4.7
Joined
·
6 Posts
Discussion Starter #10
I’m thinking it’s an output speed sensor connector. Let me know How it works out for you.
OK. Thanks for taking time for replying and trying to help. I'll let you know what I find out. One last question, if it is a Speed Sensor, wouldn't I have it on my 1999 Harness as well? The BK/RD line is missing on the 1999 14 pin connector? Oh well, I will research more and if I find the answer, I will let you know.
 

·
Registered
2014 Limited
Joined
·
296 Posts
Seeing as how one is a Q-Trac lol and the other is Q-Drive Ithink that’s where you’re difference is. One thing, if you pulled them both don’t you remember where they cam out of? I know when I started pulling my 04 for resto, I had to order some parts that were late model 03. You could always run to the dealership and try and order that connector and see what they lost it as. If you don’t have any that’s you can try let me know and I can try to get the info from a High School friend that runs our Dealership parts dept.
 
1 - 11 of 11 Posts
Top