Renix vs HO vs OBD-II: which 4.0L Cherokee XJ do you have?
5 Verified2 Single source1 Sources conflict3 Not yet verified
Short answerShow me the answer
Model year is the quickest guide. 1987–90 4.0L XJs use the Renix engine computer, which sits under the dash to the right of the steering column [1][2][3]. 1993–95 trucks flash trouble codes on the check engine lamp when you turn the key On-Off-On-Off-On [6][7][4]. 1999–2001 trucks have an OBD-II port under the dash near the steering column [8][12], and 2000–01 trucks dropped the distributor for a coil rail [10][11][13]. Unverified The 1991 HO and 1996 OBD-II year breaks come from Wikipedia only and aren't confirmed by a factory source yet [1].
| 1987–90 (Renix) | Computer under dash, right of the column [2][3] |
|---|---|
| 1991–95 (HO) | Key On-Off-On-Off-On flashes codes (1993–95) [6][7][4] |
| 1996 | Unverified OBD-II, per Wikipedia only [1] |
| 1997–2001 | OBD-II port near the steering column (1999–2001) [8][12] |
| 2000–01 ignition | Coil rail, no distributor or plug wires [10][11][13] |
The short version
| Model years | Engine computer | What it means for you |
|---|---|---|
| 1987–90 | Renix | Computer under the dash, right of the steering column.[2][3] Unverified No codes you can read. (enthusiast reference only)[14] |
| 1991–95 | 4.0 HO (Chrysler) | Codes flash on the check engine lamp (1993–95).[6][7][4] |
| 1996 | OBD-II | Unverified Old body, OBD-II computer. (Wikipedia only)[1] |
| 1997–99 | OBD-II | OBD-II port near the steering column (1999).[8][12] |
| 2000–01 | OBD-II | Coil rail; no distributor or plug wires.[10][11][13] |
How to tell which you have
- Check the model year on the title or VIN plate. It’s the quickest guide.
- 1987–90 Renix: the engine computer is under the dash, to the right of the steering column.[2][3]
- 1993–95: turn the key On-Off-On-Off-On within 3 seconds, ending On. The check engine lamp displays any stored codes as a series of flashes, one group per digit.[6][7][4] Unverified On 1994 trucks, the diagnostic connector for a scan tool is in the engine compartment. (factory manual only)[6]
- 1999–2001: the OBD-II port is below the lower edge of the dash, near the steering column.[8][12]
- 2000–01: no distributor and no spark plug wires. A one-piece coil rail bolted to the cylinder head holds three coils, each firing two plugs (cylinders 1–6, 2–5 and 3–4).[10][11][13]
Power ratings
Why it matters for repairs
- Sensors and connectors differ. The 1987–90 crankshaft position sensor has its own Chrysler bulletin and replacement kit.[2] See the CPS guide for the right part for your year.
- Fuel pressure changed. 1993–95 trucks use a return-type system: about 31 psi (214 kPa) at idle with the regulator vacuum line on, and about 39 psi (269 kPa) with it off.[6][7][5] Unverified The 2000 manual gives 49.2 ± 5 psi (339 ± 34 kPa) for a returnless system. (factory manual only)[9]
- Ignition. 2000–01 trucks have no distributor or plug wires, so cap-and-rotor advice doesn’t apply.[10][11][13] Plug gaps and firing order are on our firing order page.
Verified values
Not yet verified
| Item | Value | Applies to | Sources | Status |
|---|---|---|---|---|
| 1987–90 trouble codes | The Renix computer does not flash or store trouble codes for an owner to read | Enthusiast reference only | Report this value | Not yet verified |
| 1987–90 power rating | Wikipedia: 173 hp (1987), 177 hp (1988–90). 1988 service data: 173 hp | 1987–90 4.0L | Sources (2) | Sources conflict |
| 1991–95 HO power rating | 190 hp (1993 data gives 190 hp at 4750 rpm) | 1993 data; Wikipedia | Sources (2) | Not yet verified |
| Diagnostic connector, 1994 | In the engine compartment | 1994 factory manual | Report this value | Single source |
| 1996 is OBD-II | 1996 trucks use OBD-II | Wikipedia only | Sources (1) | Not yet verified |
| Fuel pressure, 2000 | 49.2 ± 5 psi (339 ± 34 kPa) at the injectors, returnless system | 2000 factory manual | Sources (1) | Single source |
FAQ
What years are Renix Jeep Cherokees?
How do I read codes on a 1991–95 Cherokee?
Is a 1996 XJ OBD-I or OBD-II?
Unverified OBD-II, according to Wikipedia [1]. We don't yet have a 1996 factory source to confirm it.
Where is the OBD-II port on a Jeep Cherokee XJ?
Sources (14)
- Wikipedia, "Jeep Cherokee (XJ)"
- Chrysler service bulletin 18-51-88, crankshaft position sensor and harness replacement, 1987–90 4.0L (reproduced by johnmeister.com)
- 1988 Cherokee service data, 4.0L engine specifications and engine control system; third-party (archive.org item titled "Factory Service Manual" but not a Chrysler publication)
- 1993 Cherokee service data, engine specifications and self-diagnostics; third-party (archive.org item titled "Factory Service Manual" but not a Chrysler publication)
- 1993 Engine Performance, 2.5L & 4.0L Basic Diagnostic Procedures; third-party service data (reproduced by johnmeister.com)
- 1994 Jeep Cherokee and Wrangler Service Manual (Chrysler 81-370-4146), Group 14 fuel system and Group 25 emission controls (archive.org OCR scan)
- 1995 Jeep Cherokee and Wrangler Service Manual (Chrysler 81-370-5146), Group 14 fuel system and Group 25 emission controls (archive.org OCR scan)
- 1999 Jeep Cherokee Electronic Service Manual (Chrysler 81-370-9146), Group 25 emission controls (archive.org OCR scan)
- 2000 Jeep Cherokee (XJ) Service Manual, Group 14 Fuel System (PDF reproduced by johnmeister.com)
- 2000 Jeep Cherokee (XJ) Service Manual, Group 8D Ignition System (PDF reproduced by johnmeister.com)
- 2001 Jeep Cherokee (XJ) Service Manual, Group 8D ignition system (archive.org OCR scan)
- alloemmanuals.com, 2001 Cherokee, "Checking Minimum Airflow (2.5L & 4.0L)" (OEM-derived service data)
- alloemmanuals.com, 2001 Cherokee, "Ignition Coils (4.0L) (theory and operation)" (OEM-derived service data)
- ihatethiscar.com, "XJ 4.0L Renix Wiring Diagnostic Quick Reference (1987–1990)"
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