CCM Code H72

[XfireZ51]

Serial Data Link Error. Anyone else run into this problem? If so, what did you find to be the problem?

[Toyvet1]

When I had that issue was when I removed the radio receiver. There are two connectors that you can cross connect. Took Jeff and me a couple hours to fix my stpid mistake...

[Marc Haibeck]

Hi Dominic,

A data scanner can cause the CCM 72 error because the scanner can hog the serial data buss.

The problem can occur if the ECM calibration model year does not the match the CCM MY.

If the fuel use data is displayed on the cluster the serial data line between the ECM and the CCM is working.

[XfireZ51]

Originally Posted by Marc Haibeck

Hi Dominic,

A data scanner can cause the CCM 72 error because the scanner can hog the serial data buss.

The problem can occur if the ECM calibration model year does not the match the CCM MY.

If the fuel use data is displayed on the cluster the serial data line between the ECM and the CCM is working.

Marc,

As always thanks for taking the time to provide an answer. I have seen the code whenever I connect with my EASE scantool. For some reason this time, the scantool was not connected. I had been driving around when I had to stop at a railroad crossing. It was a slight incline. Shut the motor off since this was a 2 mile freight train. Crossing clears and I start motor to move, engine stumbles, Service ASR and Service Engine light pop on along with high idle. Car runs poorly for a bit but things seem to clear up with car being operable. Both lights stay on. When I get home, I plug in code scanner. No code for the ECM, just 12 Flashing. Ground ALDL pin G,
and I get H72 on Module 9.
FSM suggests wiggling EBCM harness connectors to see if I could recreate. Nothing showing up at this point. Same thing happened on way out of BG last Sunday. Paul and I stopped for gas before hitting 65. I shut motor off. When I turned it back on, I got SES and SASR light. Didn't take the time to read codes, I just drained the batt, and went home. However, motor just didn't feel as crisp but did not encounter any further codes.

[XfireZ51]

SNL Weekend Update:

So I'm reading threads here about how some have experienced their motor running just fine and then nothing!. That after 2 years someone discovered that they had ohm'd some injectors and inadvertently done so from the front of the ECM connector, not back probe. This then causing the female connector to be somewhat "loose" (ok get your mind out of the gutter) and causing an intermittent gremlin. Speaking of gremlins, I loved the ones Bugs Bunny would run into when he was flying a plane.
Tuning my motor with the Pete the Greek "VUNDER CAMS", I continue to experience some issues with stalling (DFCO is diabled for tuning purposes)
at idle. Having read the thread I decided to dissconnect the ECM, take some contact cleaner and get some of the 20 years of oxidation off. Well it certainly looked as if the connectors had not been moved since the car came from BG Assembly. Once cleaned and reassembled, I put my scan tool on the motor to check that nothing had been damaged in the cleaning.
This is something is always do when fooling with the ECM. In fact, whenever I am going to do a datalog, I always begin logging at 0 rpm with only ignition ON. This shows me sensor readings that should be nominal. That way I know the sensors are operating in range before logging operating data. Well, KEY ON, SES light blinks like it should but MAP and TPS voltages and readings are skewed. MAP is reading 79kPa, TPS is reading 23%,1.33 volts.
Step by step, I eliminate Ostrich 2.0 and Moates adapter. Using stock chip, KEY ON, TPS and MAP readings are normal. OK, is it the Ostrich or the Moates Adapter? I re-install adapter but this time with a chip I had burned for the trip to BG. Readings are incorrect with same values.
SO something is up with the adapter.
On the last datalog I ran, my BLMs appeared locked at 128 even though I had O2 sensor voltage and Closed Loop.
Could this be the cause of my H72 code when I hadn't used the scantool? Works fine when cold and the at hot engine temps, motor idles a bit erratic with a periodic stumble.