recently got a 99 xj and was told it had a bad ecm. the ecm has been replaced and now it is showing a p1698 as well as p1899. there was no CEL with the old ecm. I checked connections at the ecm, the tcm and the grounds, looked for deteriorated wiring and now I'm at a loss. should I start looking for a new tcm? please help!

 

P1698 is an odd duck code and usually shows up on '97 & '98 AW4's. P1899 is also an odd duck. It points at an AW4 Park Neutral Position Switch issue, which confuses me.

My first thoughts are that the TCM is bad or the Transmission Range Sensor (NSS) is bad, or the wiriing associated with these units is defective. A TCM replacement has fixed P1698 issues on '97 & '98 AW4's, but with a '99, I'm not sure.

 

tcm? O2 sensor? I tested the tps with a multimeter and it appears to be properly functioning. any more ideas? thanks

 

Do you have a 2.5L engine in this Jeep?

What is the part number on the side of the PCM (ECM) that was installed? It could be the wrong one for your Jeep.