2015 Sierra, Whipple, MAF harness modifications, Baro Breakout and IAT + REP Mode

[lippmoney]

Hey there gang,

Issue: REP Mode has chosen violence and wont leave

Background: truck is coming off of a minor rebuild due to failed lifter and all of the fun that involves. I am now troubleshooting wiring that i did 3 years ago and my old ass memory is failing me. I'm hoping someone with a higher grade of vehicle based autism than the version i got can help me out here. I realize REP mode can come from a variety of sources - i just want to eliminate some questions in my head.

Wiring of MAF -> TMAP -> Baro Breakout (and sensor) -> ECU. Someone check me here. I need to know if these are indeed relocations or are they splices into the existing circuit maintaining the original signal routing and simply tying in / sharing the signal?

MAF: de-pin MAF pin #1 (IAT Signal) and connect to new 4 wire, 3 bar MAP at rear of blower, creating TMAP. connect relocated MAF wire to new MAP pin #2
MAF: de-pin MAF pins #2, 3 and 4 (TIAP 5v Ref, TIAP Low, TIAP Signal) and reroute to existing 3 wire MAP for new Baro sensor installed free-air wherever.

That leaves 4 wires left connected to the MAF: pin 5: power supply, pin 6: MAF signal, Pin 7: signal ground, pin 8: humidity signal. These pins and wires are untouched.

I removed the connectors provided by whipple a long time ago so nice convenient breakout harnesses are not an option. My question is are these wire relocations or are they splices?

Thank you!!

[GHuggins]

Hey there gang,

Issue: REP Mode has chosen violence and wont leave

Background: truck is coming off of a minor rebuild due to failed lifter and all of the fun that involves. I am now troubleshooting wiring that i did 3 years ago and my old ass memory is failing me. I'm hoping someone with a higher grade of vehicle based autism than the version i got can help me out here. I realize REP mode can come from a variety of sources - i just want to eliminate some questions in my head.

Wiring of MAF -> TMAP -> Baro Breakout (and sensor) -> ECU. Someone check me here. I need to know if these are indeed relocations or are they splices into the existing circuit maintaining the original signal routing and simply tying in / sharing the signal?

You have a PD blower. You don't need the baro breakout at all... Pin 1 of the MAF's originally wiring gets cut. Wire to ECM then gets routed to the TMAP

MAF: de-pin MAF pin #1 (IAT Signal) and connect to new 4 wire, 3 bar MAP at rear of blower, creating TMAP. connect relocated MAF wire to new MAP pin #2
MAF: de-pin MAF pins #2, 3 and 4 (TIAP 5v Ref, TIAP Low, TIAP Signal) and reroute to existing 3 wire MAP for new Baro sensor installed free-air wherever

You only mess with pin 1 for the TMAP - attached images for wire move arounds as the TMAP is wired differently than the stock map.

That leaves 4 wires left connected to the MAF: pin 5: power supply, pin 6: MAF signal, Pin 7: signal ground, pin 8: humidity signal. These pins and wires are untouched.

I removed the connectors provided by whipple a long time ago so nice convenient breakout harnesses are not an option. My question is are these wire relocations or are they splices?

Thank you!!

[lippmoney]

i know i dont need it - however, this is how the tune has been setup. the thinking at the time (2 years ago) was that the broken out baro would make tuning easier, so that's what was done. it works fine when things are wired correctly. i have the PCM of NC sciap harness but dont want to unwind everything that's already done. not yet at least..

i'll revert back to original MAF wiring - and continue down the trouble shooting path on 5V ref circuit and REP mode. hopefully this fixes it...

[edcmat-l1]

REP mode is always accompanied by a trouble code or multiple. I don't see where one was posted. That would be the place to start.

[lippmoney]

REP mode is always accompanied by a trouble code or multiple. I don't see where one was posted. That would be the place to start.

cleaned up some wiring issues (burnt harness near bank 2) upon startup now i get "MAP TPS Fail TMS" in my MAF status portion of the datalog. Permanent codes have been dealt with. P0107 is the suspect. i'll have to dig in on that one. P06DA is one i need to shut off from VVT delete... or wire in a resistor.

0x7E8: P0097 - Intake Air Temperature Sensor 2 Circuit Low (Permanent)
0x7E8: P0107 - Manifold Absolute Pressure/BARO Sensor Low (Pending, Current, Old)
0x7E8: P0480 - Fan 1 Control Circuit (Permanent)
0x7E8: P0521 - Engine Oil Pressure Sensor/Switch Circuit Range/Performance (Permanent)
0x7E8: P0621 - Generator Lamp Terminal Circuit (Pending, Current, History)
0x7E8: P0691 - Fan 1 Control Circuit Low (Permanent)
0x7E8: P06DA - Engine Oil Pressure Control Circuit / Open (Pending, Current, Old)

[1slow1500]

I also am having similar issues and wondering if it has to do with my baro breakout. because of the turbo. i was going to replace that map sensor then upgrade the intake bolts, maybe a leak not sure.
I also got a cylinder6 missfire under load. very odd.
I did cam package and all was ok before other the tick noise. new plugs and wires.
B3926
B3980
u0101
p0106
p0107
p0300
p16a1

Think you maybe onto something with the with sensor config. i will try that also.

[lippmoney]

I also am having similar issues and wondering if it has to do with my baro breakout. because of the turbo. i was going to replace that map sensor then upgrade the intake bolts, maybe a leak not sure.
I also got a cylinder6 missfire under load. very odd.
I did cam package and all was ok before other the tick noise. new plugs and wires.
B3926
B3980
u0101
p0106
p0107
p0300
p16a1

Think you maybe onto something with the with sensor config. i will try that also.

it wasnt making sense. everything was going right back in the way it came out and it was running fine previously. Some interesting info out of Alldata on REP mode - take a look at the portion in italics:

Reduced Engine Power Mode

When the ECM detects a condition with the TAC system, the ECM may enter a reduced engine power mode. Reduced engine power may cause one or more of the following conditions:

Acceleration limiting?The ECM will continue to use the accelerator pedal for throttle control, however, the vehicle acceleration is limited.
Limited throttle mode?The ECM will continue to use the accelerator pedal for throttle control, however, the maximum throttle opening is limited.
Throttle default mode?The ECM will turn OFF the throttle actuator motor and the throttle will return to the spring loaded default position.
Forced idle mode?The ECM will perform the actions listed below:
Limit engine speed to the idle position
Ignore the accelerator pedal input.

Engine Shutdown Mode

There are 4 reasons the ECM commands engine shutdown. All 4 reasons involve a throttle that has been commanded to default position ? Reduced Engine Power. Default Throttle is latched for the key-cycle, disabling the throttle motor and letting the spring return the throttle to its default position. Default Throttle by itself does not cause a commanded shutdown. Shutdown will only occur with Default Throttle and another issue. A throttle is commanded to Default Throttle when any of the following occurs:

SENT Sensor Communication Faults ? P16A0?P16A2, U0606, or U0607
Performance Faults ? P0068, P2101, or P2176
Sensor Reference Voltage Fault ? P06A3
Internal Sensor Faults ? P0122, P0123, P0222, P0223, or P2135

The ECM commands engine shutdown when any of the following occurs:

Default Throttle & Catalyst Temperature to high ? In order to idle in Default Throttle the spark is often retarded quite a bit, dumping a lot of heat into the catalyst.
Default Throttle & P2119 ? The throttle sensors detect that the throttle position is higher than default position and throttle hasn?t safely returned to default position.
Default Throttle & P16F3 or P0606 ? The calibration does not trust the ECM to determine if the throttle has safely returned to default position.
P0068 and any SENT Communication Fault, Reference Voltage Fault, or any of the 5 Sensor Faults ? The ECM detects excess air flow based on expected default throttle position indicating the throttle position is higher than the default throttle position. The calibration does not trust the faulted throttle sensors to determine if the throttle has safely returned to default position.

Also need to check my ECT sensor... and some other things...

[1slow1500]

So I'm not a pro as others on these forums. but My truck is low miles(15,400) and I had to do the service bulletins on block, dash and frame grounds. As well as the cable part#. but when I was in the motor I did the oil sensor filter/screen( most replace the sensor also). also there was a way to test out your sensor wires with a digital meter vs. voltage in log.

I switched to TIAP and it took 10minutes but all the baro and sensor issues are cleared. I checked 5 times in 45minutes all came up no codes. sent email to request input on code reset times to buddy at gm. Sounds like miles,time, and also the sensor seeing the % all play a factor.
sounds stupid but check that the values for the maps are set to the correct values.
*Baro is my stock map then ls9 map in "manifold"

Have you looked at a comparison file to a good whipple file?

[lippmoney]

So I'm not a pro as others on these forums. but My truck is low miles(15,400) and I had to do the service bulletins on block, dash and frame grounds. As well as the cable part#. but when I was in the motor I did the oil sensor filter/screen( most replace the sensor also). also there was a way to test out your sensor wires with a digital meter vs. voltage in log.

I switched to TIAP and it took 10minutes but all the baro and sensor issues are cleared. I checked 5 times in 45minutes all came up no codes. sent email to request input on code reset times to buddy at gm. Sounds like miles,time, and also the sensor seeing the % all play a factor.
sounds stupid but check that the values for the maps are set to the correct values.
*Baro is my stock map then ls9 map in "manifold"

Have you looked at a comparison file to a good whipple file?

i have all of the previous versions of tunes that al;l; worked perfectly before, the tune isnt the issue on my side. it's definitely a wiring / install issue.

question for you...

you have your stock map (which is your new baro) wired in to where? the TIAP wires X1: #4, #5 and X2: #69? and your LS9 map wired into the old map pins X2: #43, #44, #63?

whipples instructions are seriously lacking...

[1slow1500]

stock map wired to the maf wires. and the ls9 map is in the stock harness and location( then values added to tune). can't remember what pins this was many years ago. As I recall the stock sensor in the maf wires i installed didn't require any values to be changed. I believe Tiap values for boost and SCIAP for for vacuum.

[lippmoney]

*RESOLVED*

for future problem hunter - broken TMAP signal wire in connector - that was a REAL MF to find.