help with nss issue, please!

I have searched and searched and searched, I have a 98 xj sport, all stock (for now) 198,000. I bought it with 125,000. When I bought it it had a code for the nss, reverse lights didnt work, and it starts in every gear. When my flexplate got bad, I pulled the tranny, and decided to clean my nss. Well, I broke it trying to get it off. So I bought a crown automotive replacement. Now, my reverse lights work, but I still have the p1899 code showing, and it wont go away. I adjusted the switch per the forum, per mitchell, and every fraction of adjustment it has. I have verified that the switch is showing all gear selector positions, I had it to the point that it would not show proper gear positions and lost overdrive. So in a nutshell, p01899, starts in any gear, but scan tool shows its getting proper positions, and now my reverse lights work. I want to get rid of the check engine light........I am an alignment guy at a shop and we have a scan tool. I am no crack tech, but to me it would seem that I got a bad switch. I was hoping someone could let me know if I have missed something. I dont want to return this part if it acually good. I have a good relationship with the parts store, and dont want them to warranty a part that is good. (bad for their business) he gives me good deals. Could I have messed up something when I pulled the tranny? All wiring apears un molested. No splices or hack jobs that I have found since I bought it 6 years ago. Thank you in advance for any help. 98 cherokee sport. 4.0, aw4, no awd feature of the transfer case. Runs and drives great.

http://www.justanswer.com/jeep/2dzht-check-engine-light-code-i-m-getting-p1899.html

this is about all i can give you. check the continuity of the wires with an ohm meter. he lists how in that thread.

Possible causes: p1899

Intermittent NSS sense circuit
NSS
NSS sense circuit shorted to ground
PCM

I would first disconnect the Transmission Range Sensor (NSS) harness connector near the engine.

Inspect both sides of the plug connector for pulled or bent pins, corrosion, damage, etc.

NSS connector near engine
--------------------------------
Harness side - Pin 7
NSS plug ...... Pin 7

If NSS plug & connector are ok then the problem may be with the PCM or PCM wiring, (resistance - ohms) between PCM C1 to the NSS.

PCM C1 (plug) Pin 6 <<<<--->>>> Pin 7 (NSS connector) NSS sense wire (should be the black / white wire)

The wiring schematics shows the sense wire (bt/wt) also has a connection to the starter relay ... cavity - C6

The NSS and PCM use ground connections for certain functions. Renewing ground connections sometimes alleviates problems.

I sometimes use dialectic grease for connectors that are prone to corrosion.

I did check the plug and visable wiring........looks good. It looks like I need to do some checking on wiring. I may have to call a buddy who is an airplane wiring diagnostics guy. I have mitchell at work and get him the wiring diagram.
I was hoping I missed something easy.........guess not. Thanks for the help guys!

Further testing:

Testing wire resistance:

Ignition OFF
Disconnect PCM C1 harness connector
Disconnect NSS harness connector

Measure sense circuit resistance between
PCM C1 Pin 6 and NSS connector Pin 7

Resistance should be below 5 ohms.

Short to ground test:

NSS sense circuit and ground

Resistance should be above 5 ohms

NSS Test: NSS sense circuit

Ignition Off

Move the gear selector through all gear positions, from Park to 1st and back. While moving the gear selector through the gear positions, measure the resistance between ground and the NSS switch sense circuit in the PCM C1 harness connector.

Resistant readings should change from above 10.0 ohms to below 10.0 ohms.

Here are some pinouts - The diagrams and pinouts indicate Pin 6 from the PCM C1 and Pin 7 from the NSS connector to be the Sense Switch Circuit as described in the FSM. The FSM shows that P1899 DTC is related to the performance of the Sense Switch Circuit between the PCM C1 and NSS connector. I could not find any additional information.



1998 XJ

Note:

The above information about troubleshooting and diagnostics, is from a 2001 XJ FSM. I'm not sure what changes, if any, were made between 98 and 01.

Here is a link that discusses similar diagnostic similar troubleshooting procedures for a 2000 Grand Cherokee.

http://www.2carpros.com/questions/jeep-cherokee-2000-jeep-cherokee-engine-light-on--2

If the problem is not with the NSS then it's most likely there is a problem with grounding, sense circuit or the PCM.

Thanks again!

Bobbo said:

Thanks again!

Click to expand...

Glad to help. Let us know what you find. Through forum feedback and discussion we can learn more about the Jeep and use this information for future diagnostics and repairs.