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How to check trouble codes in a 1990 4.0?
Thread Starter
Junior Member
Joined: Sep 2009
Posts: 36
Likes: 0
From: Levittown, PA
Year: 1990
Model: Cherokee
Engine: 4.0
I need to check for trouble codes in a 1990 renix 4.0. The haynes manual says the diagnostic connector is on the driver side fender well. I cant find it as I am not sure what it looks like. The manual doesnt show a picture. Is it a connector that I pull apart? Can any body give me a better idea as to where the connector is located?
Junior Member
Joined: Nov 2009
Posts: 40
Likes: 0
From: Columbia, MO
Year: 1990
Model: Cherokee
Engine: 4.o
im pretty sure the conectors you are looking for are under the hood on the passenger side with little yellow caps the only problem is i have never been able to find the right tool since it uses obd1 i think if you figure anything out let me know
Thread Starter
Junior Member
Joined: Sep 2009
Posts: 36
Likes: 0
From: Levittown, PA
Year: 1990
Model: Cherokee
Engine: 4.0
To the best of my knowledge, a 1990 is pre obd1. You dont need a code reader, you just need to bridge 2 leads on the diagnostic connector and flash the codes. This connector is what I cant find.
CF Veteran
Joined: Mar 2010
Posts: 47,923
Likes: 38
From: Broward County Fl.
Year: 1989 xj sport 2dr
Model: Cherokee
Engine: 12 hole bosch Injectors
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CF Veteran
Joined: Mar 2010
Posts: 47,923
Likes: 38
From: Broward County Fl.
Year: 1989 xj sport 2dr
Model: Cherokee
Engine: 12 hole bosch Injectors
ok go to this link and searc renix you can only get codes that way if you have a v6 engine they hade check engine lights
CF Veteran
Joined: Mar 2010
Posts: 47,923
Likes: 38
From: Broward County Fl.
Year: 1989 xj sport 2dr
Model: Cherokee
Engine: 12 hole bosch Injectors
CF Veteran
Joined: Apr 2008
Posts: 2,237
Likes: 3
From: Northern Illinois
Year: 90
Model: Cherokee
Engine: 4.0
Okay... we seem to go through this every few months.....
You can't check trouble codes on a Renix 4.0. The system doesn't store any...
The DRB2 connector(under the hood) connected to a live scanning system. There was a factory system and one from Snap-on. Have a fun time finding either... They were not terribly common back when, and are even rarer now. You however can check every single sensor output with a multimeter.
Billavista has a excellent series of articles on his site.
And freegdr... if you find a US market Jeep V-6 that is Renix, let me know... The 2.8 is a Chevy motor and used the Chevy control system(what little there was)
You can't check trouble codes on a Renix 4.0. The system doesn't store any...
The DRB2 connector(under the hood) connected to a live scanning system. There was a factory system and one from Snap-on. Have a fun time finding either... They were not terribly common back when, and are even rarer now. You however can check every single sensor output with a multimeter.
Billavista has a excellent series of articles on his site.
And freegdr... if you find a US market Jeep V-6 that is Renix, let me know... The 2.8 is a Chevy motor and used the Chevy control system(what little there was)
Your jeep is a "renix", the ECU is built by Renault/Bendix (known for their aeronautic/race engine management)
Renix is PRE OBD, there is a scanner, but its proprietary and I dont think the dealers even keep them around any more. It would be very hard to find one. It would be kinda useless anyway, Since The Renix ECU does not have much on the way of diagnostics.
The information that was not put into KAM or "Permanent" memory is not stored. This is information like "soft" codes, etc. Any "hard" codes (failures lasting more than 2 seconds) are kept in memory after the key is turned off. The fuel map is stored and so are other vehicle information.
There are no CELs since its PRE-obd and everything can be tested with a multimeter and some time.
The renix takes a few seconds to start, it has more parameters that need to be met before it will fire, unlike the newer models.
Renix is PRE OBD, there is a scanner, but its proprietary and I dont think the dealers even keep them around any more. It would be very hard to find one. It would be kinda useless anyway, Since The Renix ECU does not have much on the way of diagnostics.
The information that was not put into KAM or "Permanent" memory is not stored. This is information like "soft" codes, etc. Any "hard" codes (failures lasting more than 2 seconds) are kept in memory after the key is turned off. The fuel map is stored and so are other vehicle information.
There are no CELs since its PRE-obd and everything can be tested with a multimeter and some time.
The renix takes a few seconds to start, it has more parameters that need to be met before it will fire, unlike the newer models.
CF Veteran
Joined: Mar 2010
Posts: 47,923
Likes: 38
From: Broward County Fl.
Year: 1989 xj sport 2dr
Model: Cherokee
Engine: 12 hole bosch Injectors
::CF Moderator::
Joined: Aug 2011
Posts: 43,971
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From: Prescott, Az
Year: 1990
Model: Cherokee (XJ)
Engine: 4.0





