What could be cause of P0488 & circuit voltage code . 2008 Cab&Chassis

[GardnerM]

Also the check guages light comes on and chimes. Just got it all buttoned up with new injectors,head gasket ,dpf,egr delete with Race Me tuner Finally almost there. Do I need sims foolers ? Has two new batteries..I tried clearing by pressing brake ,then throttle..

 

[DonFitzwater]

Isn't that a throttle valve circuit code? Is your throttle valve gone?

 

[GardnerM]

Isn't that a throttle valve circuit code? Is your throttle valve gone?

Its still intact . Wonder if it needs eliminated

 

[GardnerM]

Or I mean the egr valve at intake is there

 

[xcc_rider]

Did you unplug the TCV when you deleted?

 

[GardnerM]

Yes ,now I cleared the 0488 code and drives awsum for about eight miles,then I get a ding ding "check guages" , then another ding ding and on the overhead console I get "service required", then "see dealer now" then it had about a third of the power. I shut off put key to on ,depress brake twice,then slowly the throttle ,seems to clear it for several minutes then ding ding. Maddning!!

 

[xcc_rider]

It's another problem and not tune related. Reloading the tune or clearing the message only masks the problem until the ecm runs thru its self diagnostics cycle and triggers the message and limp mode again.
If the TCV is unplugged and you're getting a low circuit code then there's a voltage loss (short to ground or between two wires) somewhere in the TCV harness.
I'd start with checking the wiring pigtail to the TCV (not egr) for chaffing.

 

[GardnerM]

Ill run that down .Being temped to drive it in the the big shop but if I can res0k

 

[GardnerM]

Resolve it here then even better .

 

[GardnerM]

I just went out and felt around and the TCV at intake is plugged in. So is it closed when parked ,or is it open and normally would close during regen ? EGR is delected and I have the Race Me installed..

 

[xcc_rider]

The TCV is open at key off. Its normally open when running and closes off a bit to increase the egr flow as needed. IIRC, the TCV and egr are not used during regen but are used during one or more of the desorb cycles.

I'm not that familiar with the C&C deletes but on our trucks the TCV is unplugged when tuned cwith the Raceme tuner.

 

[GardnerM]

Thanks ,and I would imagine it should be unplugged and hopefully that is why it is sending the CEL and check guages. Now if I can figure out the quick and easy way release that plug. Some you can get by with squeezing and they pull apart .

 

[GardnerM]

Now after unpluggin TCV so far no p0488 ,but keep getting the check guages ding ding and light after she warms up

 

[xcc_rider]

Is the light the cel, check gauges or lightning bolt?
If cel then you can pull the pending codes. If lightning bolt then I want to say its electrical. If check gauges then I'm lost like you.

There's a reason you were getting the P0488 low circuit voltage code. Considering all the work that was done it isnt hard to imagine that the harness may have been damaged. At least it's something to check.
Beyond that maybe make a new post highlighting the dings and check gauges part and see if you can get some forum input. Include the 0488 code and unplugging the TCV status in the post and see what you get.
You're probably not getting a code now because its disconnected but there's still a short somewhere in the harness that's triggering the dings and check gauges light.

 

[GardnerM]

Only have a PO6EC code now so the harness is suspect. Crossover harness maybe . Now to round up all new terminals (military spec ,hope Napa has it. ) My neighbor has a crimper..But for an 08 would there be enough lost in these cables , or is my connections rinky dink is the question. Not condemning alternator yet. Ill test voltage at terminals on drivers and pass.

 

[GardnerM]

Sorry ,its a PO63C code I get now.Thats it. Im getting 14.8 on both posts??

 

[xcc_rider]

From the code diagnostics:
Theory of Operation
There are two communication lines between the ECM and alternator. Based on sensed battery voltage, the ECM commands the alternator to charge the batteries to a desired voltage. The max voltage the ECM will command the alternator to charge is 14.75 volts. The ECM then receives feedback from the alternator on the voltage level it is charging the batteries. The ECM will not light a MIL lamp for this fault. • When Mon itored: Engine running .
• Set Condition: Battery voltage exceeds charging voltage by more than a calibrated amount for a calibratable period of time.
Possible Causes
DAMAGED, CORRODED, OR LOOSE CONNECTIONS (A804)
GENERATOR SENSE CIRCUIT SHORTED TO GROUND (A804)
GENERATOR SENSE CIRCUIT OPEN
OPEN CIRCUIT BETWEEN GENERATOR AND AUXILIARY BATTERY
GENERATOR
ECM
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE DIAGNOSIS AND TESTING)
Diagnostic Test 1. BATTERY TERMINALS DAMAGED, CORRODED, OR LOOSE CONNECTIONS
NOTE: Batteries must be fully charged and capable of passing a battery load test. The generator belt tension must be within specification. Inspect the vehicle for any aftermarket equipment that may exceed the maximum generator output. Visually inspect the positive and negative connections at the battery. Visually inspect the battery negative connections at the engine block. Are the connections free of corrosion and are they tight?
Yes »Go To 2 No »Clean and/or tighten the connections. Perform POWERTRAIN VERIFICATION TEST - 6.lL. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
2. (A804) GENERATOR SENSE CIRCUIT SHORTED TO GROUND Turn the ignition off. Disconnect the C1 ECM harness connector. NOTE: Check connectors - Clean/repair as necessary. Measure the resistance between the (AB04) Generator Sense circuit at the ECM harness connector and ground. Is the resistance greater than 100 k Ohms?
Yes »Go To 3 No
»Repair/replace harness for a short to ground. Perform POWERTRAIN VERIFICATION TEST - 6.7L. (Refer to 9 - ENGINE - STANDARD PROCE· DURE)
3. (A804) GENERATOR SENSE CIRCUIT OPEN Measure the resistance of the (A804) Generator Sense circuit from the alternator harness connector to the ECM harness connector.
Is the resistance less than 10 ohms?
Yes »Go To 4 No
»Repair/replace harness for an open circuit. Perform POWERTRAIN VERIFICATION TEST - 6.7L. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
4. OPEN CIRCUIT BETWEEN GENERATOR AND AUXILIARY BATTERY Disconnect the positive battery cables from both the primary and auxiliary battery. Disconnect the harness from the auxiliary battery to the generator. Measure the resistance in the harness that connects the auxiliary battery to the generator. Is the resistance less than 10 ohms?
Yes »Go To 5 No
5. GENERATOR
Measure the resistance between the generator output stud and the generator Sense circuit on the generator connector. Is the resistance less than 10 ohms?
Yes »Replace ECM. Perform POWERTRAIN VERIFICATION TEST - 6.7L. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No
»Replace generator. Perform POWERTRAIN VERIFICATION TEST - 6.7L. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
»Repair/replace open circuit in wiring harness. Perform POWERTRAIN VERIFICATION TEST - 6.7L. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

 

[GardnerM]

Ill continue on the terminals ,double check connections on alternator

 

[GardnerM]

May just take it in tomorrow where they can troubleshoot the truck indoors .Hopefully ECM is,ok

 

[GardnerM]

Never finished this thread . The alternater even though it tested good at Oreillys, tested bad at a specialty shop. Took care of that code,connections ,cables are good.