Check engine light codes P0700 and P0723 after dealer replaced my fuel pump
06-17-2017, 01:29 AM
#1
Instructor
Thread Starter
Check engine light codes P0700 and P0723 after dealer replaced my fuel pump
I just got my 08 C6 A6 vert back from the dealer after they replaced my fuel pump per the special extended warranty program they recently started. It ran great and displayed no problems until about 60 miles of driving. The engine light came on and is throwing a P0700 "Transmission Control System" and P0723 which is "Output Speed Sensor Circuit Intermittent". The way I understand it is the P0723 code is what triggers the P0700 which is a MIL. There isn't a lot of info out there (that i could find) for troubleshooting the P0723. They had to drop the trans-axle to do the work so I'm suspecting something didn't get plugged in completely. I pulled these codes with my Autoenginuity Scantool. I only have the "Enhanced Ford Software Licence" for it but it will still pull the generic codes from anything. I will be buying the Enhanced GM Software Licence Monday when the open.
I attached a snippet of the DTC's. Does anyone have any insight offer on this code combination?
I attached a snippet of the DTC's. Does anyone have any insight offer on this code combination?
Last edited by icanski2; 06-17-2017 at 01:30 AM.
06-17-2017, 03:57 AM
#2
Le Mans Master
I just got my 08 C6 A6 vert back from the dealer after they replaced my fuel pump per the special extended warranty program they recently started. It ran great and displayed no problems until about 60 miles of driving. The engine light came on and is throwing a P0700 "Transmission Control System" and P0723 which is "Output Speed Sensor Circuit Intermittent". The way I understand it is the P0723 code is what triggers the P0700 which is a MIL. There isn't a lot of info out there (that i could find) for troubleshooting the P0723. They had to drop the trans-axle to do the work so I'm suspecting something didn't get plugged in completely. I pulled these codes with my Autoenginuity Scantool. I only have the "Enhanced Ford Software Licence" for it but it will still pull the generic codes from anything. I will be buying the Enhanced GM Software Licence Monday when the open.
I attached a snippet of the DTC's. Does anyone have any insight offer on this code combination?
I attached a snippet of the DTC's. Does anyone have any insight offer on this code combination?
Perhaps you can trying reseating the external connectors on the gearbox in the hopes that a loose power connector or the like is causing a spurious P0723 to get thrown by the TCM. But if the ISS/OSS really is bad, replacement requires dropping the transmission pan and removing the valve body.
I think you may want to kick this one back to the dealer given that they were the last ones to touch it.
06-17-2017, 04:53 AM
#3
Instructor
Thread Starter
According to my service manual, P0723 is triggered by an invalid signal from the "Input and Output Speed Sensor" module (ISS/OSS), which plugs into the TCM. The thing is, both the ISS/OSS and the TCM are inside the gearbox itself.
Perhaps you can trying reseating the external connectors on the gearbox in the hopes that a loose power connector or the like is causing a spurious P0723 to get thrown by the TCM. But if the ISS/OSS really is bad, replacement requires dropping the transmission pan and removing the valve body.
I think you may want to kick this one back to the dealer given that they were the last ones to touch it.
Perhaps you can trying reseating the external connectors on the gearbox in the hopes that a loose power connector or the like is causing a spurious P0723 to get thrown by the TCM. But if the ISS/OSS really is bad, replacement requires dropping the transmission pan and removing the valve body.
I think you may want to kick this one back to the dealer given that they were the last ones to touch it.
06-22-2017, 09:41 AM
#4
Instructor
Thread Starter
Update: It appears to be healed
According to my service manual, P0723 is triggered by an invalid signal from the "Input and Output Speed Sensor" module (ISS/OSS), which plugs into the TCM. The thing is, both the ISS/OSS and the TCM are inside the gearbox itself.
Perhaps you can trying reseating the external connectors on the gearbox in the hopes that a loose power connector or the like is causing a spurious P0723 to get thrown by the TCM. But if the ISS/OSS really is bad, replacement requires dropping the transmission pan and removing the valve body.
I think you may want to kick this one back to the dealer given that they were the last ones to touch it.
Perhaps you can trying reseating the external connectors on the gearbox in the hopes that a loose power connector or the like is causing a spurious P0723 to get thrown by the TCM. But if the ISS/OSS really is bad, replacement requires dropping the transmission pan and removing the valve body.
I think you may want to kick this one back to the dealer given that they were the last ones to touch it.
I dropped it back off at the dealership first thing Saturday Morning. (Classic Chevrolet, Grapevine, TX) They put it back on the rack and checked all the electrical connections and adjusted my header/exhaust clamps so the bolts weren't pointing down causing ground clearance issues. No obvious problems were found. They sent it to their transmission guru who check what he was able to, then he reset the codes and did a test drive. The codes didn't come back. I picked it up and have been driving it every day this week and have not had any further problems. I'm thinking it was just a bad connection at this point.
On another note.... It is really nice to not have the gas fume smell in my garage after the fuel pump repair! I was dreading doing the repair myself before I got my special warranty extension letter. My service advisor at Classic Chevrolet in Grapevine, TX was Gary, and he was great to deal with. Not all dealers are bad.