KRinAZ
NAXJA Forum User
- Location
- Prescott,AZ
Hi All, I can't get any codes thrown from my ECM - it always reads "No Codes, Pass" with things like the CPS discon.
1996 Jeep XJ SE Cherokee, 4.0l, Auto Trans, 4x4, 247K miles.
How this was discovered - yesterday I was troubleshooting a "cranks but no start" condition after the Jeep engine suddenly died while driving down the hiway. Turned out to be the ignition coil.
First troubleshooting step was to hookup the Actron CP9135 scanner & found no codes. There was (unknown psi) pressure on the fuel rail. I was alone so couldn't check for spark while cranking.
I tried unhooking these sensors then cranking the motor: CPS, Distributor, expecting to throw a code & maybe get a hint where the prob was. No Code thrown. I unhooked MAP, then TPS, then Idle Solenoid (now just looking to get a code) & after cranking still no code!
Someone came along & cranked for me & I found no spark from the coil, but signal in, replaced the ignition coil & engine is running good again.
But, just to confirm what I saw yesterday, I unhooked each of the above sensors one by one & cranked the motor, & got the expected engine symptoms (either no start or runs horrible & dies) but no codes!
Everything hooked back up & engine runs great again.
The scanner does the "linking" and all that and appears to be actually communicating with the ECM.
Has anyone seen this?, scanner prob?, ECM prob?
1996 Jeep XJ SE Cherokee, 4.0l, Auto Trans, 4x4, 247K miles.
How this was discovered - yesterday I was troubleshooting a "cranks but no start" condition after the Jeep engine suddenly died while driving down the hiway. Turned out to be the ignition coil.
First troubleshooting step was to hookup the Actron CP9135 scanner & found no codes. There was (unknown psi) pressure on the fuel rail. I was alone so couldn't check for spark while cranking.
I tried unhooking these sensors then cranking the motor: CPS, Distributor, expecting to throw a code & maybe get a hint where the prob was. No Code thrown. I unhooked MAP, then TPS, then Idle Solenoid (now just looking to get a code) & after cranking still no code!
Someone came along & cranked for me & I found no spark from the coil, but signal in, replaced the ignition coil & engine is running good again.
But, just to confirm what I saw yesterday, I unhooked each of the above sensors one by one & cranked the motor, & got the expected engine symptoms (either no start or runs horrible & dies) but no codes!
Everything hooked back up & engine runs great again.
The scanner does the "linking" and all that and appears to be actually communicating with the ECM.
Has anyone seen this?, scanner prob?, ECM prob?
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