Our van was difficult to start a couple days ago, and the CEL came on. We drove a couple times before I was able to get it scanned, and the light stayed on, and it was hard starting when cold. I just scanned it and got P1607-PCM INTERNAL SHUTDOWN TIMER RATIONALITY. I searched around and couldn't find much more than that description. I cleared the code, and it's only been driven a couple miles since, and the code hasn't come back.

Has anyone dealt with this one?

 

This is a PCM internal failure code. I've seen it a few times. I would just clear it and hoping it wouldn't come back.
Also, how's your battery condition and age? Get it tested. sometimes these codes pops up when your battery voltage goes low, or weak battery.
If it does comes back, you most likely need a PCM.
PCM I under 8yr/80k miles warranty.

 

I think it has around 87k on it. The battery has been replaced sometime before we got it about a year ago. I don't really know how old it is.

 

Googled it for you & got the following, different vehicle but........ something to ponder.


Are you still under warranty????
PCM Powertrain Control Module. This is your computer. If the code is "to slow" then it is not reading and correcting systems fast enough. Keep an eye on your temp gage, it could slow your coolant cycling time. Could be as easy as a fuse so check them all to see if one is bad or if one is not tight.
This is the protocol straight out of the Chrysler shop manual.

P1607-PCM INTERNAL SHUTDOWN TIMER RATIONALITY

Test Note: All symptoms listed above are diagnosed using the same tests.

The title for the tests will be P1603-PCM INTERNAL DUALPORT

RAM COMMUNICATION.

When Monitored and Set Condition:

P1607-PCM INTERNAL SHUTDOWN TIMER RATIONALITY

When Monitored: During cold start.

Set Condition: Compares shut down time to coolant temperature.

Turn the ignition off.

Disconnect the PCM harness connector.

CAUTION: DO NOT PROBE THE PCM HARNESS CONNECTORS. PROBING

THE PCM HARNESS CONNECTORS WILL DAMAGE THE PCM TERMINALS

RESULTING IN POOR TERMINAL TO PIN CONNECTION. INSTALL

MILLER SPECIAL TOOL #8815 TO PERFORM DIAGNOSIS.

Turn the ignition to run.

Using a 12-volt test light connected to ground, probe the Fused Ignition Switch

Output (Off-Run-Start) cavity C1-12 circuit at the appropriate terminal of the special

tool #8815.

NOTE: If the test light illuminates, wiggle the wiring harness to ensure that

the problem is not an intermittent wiring problem.

Does the test light illuminate brightly?



If Yes ! Replace the Powertrain Control Module in accordance with the

Service Information.

Perform POWERTRAIN VERIFICATION TEST VER - 1.

If No ! Check all related fuses. Repair the Fused Ignition Switch Output circuit.
Also check
Inspect all PCM power and ground circuits.
Inspect and test the battery in accordance with the Service Information.
Inspect the generator drive belt for proper alignment and adjustment.
Inspect the vehicle for aftermarket accessories that may exceed the generator system output.
Inspect the fuses in the IPM. If an open fuse is found, use the wire diagram/schematics as a guide and inspect the wiring and connectors for a damaged or shorted circuit.

 

Thanks for the info. No, it doesn't have any warrantee left as far as I know. I cleaned the battery terminals today. Hopefully that helps the hard starting.

 

A little more info on the code:

P1607-PCM INTERNAL SHUTDOWN TIMER SLOW RATIONALITY
For a complete wiring diagram Refer to the Wiring Information.

Theory of Operation
The PCM compares actual shutdown time to a calculated shutdown time value. The calculated shut down time value is based on the amount the ECT should drop after a completely warmed up engine is shut down for a minimum of 8 hours. If the difference between actual shutdown time and the calculated shut down time is greater than a maximum value, a one trip failure will set. The shutdown time is measured again after 1 hour of ignition off time following the next engine warm up cycle. The PCM compares the shutdown time to a calculated value. If the difference is greater than a maximum value, the MIL is illuminated and a DTC will set.

When Monitored:
With the engine running after a cycle when a complete engine warm up was achieved, the difference between engine coolant temperature and ambient air temperature less than or equal to 10° C (50° F), and battery voltage greater than 10 volts.

Set Condition:
This DTC sets if the engine coolant temp does not drop enough or drops too much during engine off time. This DTC may also set if the controller timer is inaccurate. Two Trip Fault. Three good trips to turn off the MIL.


Possible Causes
ENGINE COOLING CONDITIONS THAT MAY SET THIS DTC
ENGINE COOLANT LEVEL
PCM INTERNAL TIMER

 

Cleaning the terminals didn't help, but I checked the voltage and it was a little low. The code never came back after I cleared it the first time. The hard start went away after I replaced the battery.