New 408 Installed Now Goes Into Limp Mode After Starting P0120 P0220 & More

[scottr126]

I recently swapped out my stock 5.3L for a 408 LQ4. I also swapped out my stock LS1 intake manifold to a Holley Hi Ram. Everything else is the same as last year when the car was running perfect. The car is running speed density.

Now when I start the car it will run for 5-10 seconds and then go into limp mode. It is DBW so I have no throttle control and a high idle at that point.

Here are the codes it throws:
0x10: P0102 - Mass or Volume Air Flow A Circuit Low (Current)
0x10: P0103 - Mass or Volume Air Flow A Circuit High (Current)
0x10: P0120 - Throttle/Pedal Position Sensor A Circuit (Pending, Current)
0x10: P0220 - Throttle/Pedal Position Sensor/Switch B Circuit (Pending, Current)
0x10: P1514 (Pending, Current, History)
0x10: P1516 (Pending, Current, History)
0x10: P1518 (Pending, Current, History)

Some other things I have noticed:
-I am getting 0 TPS voltage in scanner no matter what I do.
-Throttle moves as it should before throwing codes.
-Accelerator pedal position goes to 138% at WOT
-Throttle position (SAE) reaches 99.6% at around 60% throttle

Help!

tune 3 smoothed.hpt

[5FDP]

Maybe check the pins on the throttle body connector for damage?

Maybe a throttle relearn could help too.

Also don't forget to change the cylinder volume to match you're new motor size, it's now way larger than the 5.3 the tune is setup for.

[scottr126]

I checked the pins and they all look good.

How do I do a throttle re-learn.

At one point I did change the cylinder volume but I ended up putting the old map back in to limit the variables. What all does the cylinder volume change in the map? For some reason when I changed it to the larger volume my Main VE table numbers dropped, I would think they would go up?

Maybe check the pins on the throttle body connector for damage?

Maybe a throttle relearn could help too.

Also don't forget to change the cylinder volume to match you're new motor size, it's now way larger than the 5.3 the tune is setup for.

[scottr126]

I tested the throttle body and it seems fine. I did all of these: http://easyautodiagnostics.com/gm/4....sensor-tests-1

[Earwax]

Sounds like the TAC and APP are from different models or vehicle years.
Are the APP (pedal),TAC module from the same vehicle?
Codes 120,220,1514,1516 are all TAC, APP codes.
The APP,TPS readings have to match.If not it sets codes and goes into rep.
Check your connections as stated above. Also check the GNDs.
You can log the actual pedal position vs desired pedal position.
Check the TPS the same way. Use % for testing.
Here is a link to Gen 3 DBW: Post#6
https://www.hptuners.com/forum/showt...508#post490508

https://www.hptuners.com/forum/showt...738#post489738

[scottr126]

The throttle body and all electronics are from the same vehicle, a 2003 5.3L Avalanche. Before the motor swapped it all worked fine.

Pedal position goes up to about 138% and at about 60% pedal position the throttle body pegs at 99.6%

Is any of that adjustable?

Sounds like the TAC and APP are from different models or vehicle years.
Are the APP (pedal),TAC module from the same vehicle?
Codes 120,220,1514,1516 are all TAC, APP codes.
The APP,TPS readings have to match.If not it sets codes and goes into rep.
Check your connections as stated above. Also check the GNDs.
You can log the actual pedal position vs desired pedal position.
Check the TPS the same way. Use % for testing.
Here is a link to Gen 3 DBW: Post#6
https://www.hptuners.com/forum/showt...508#post490508

[Earwax]

I compared your tune to a good Gen 3 tune.
There are quite a few differences between the two in the ETC ,TPS 1514 areas.
Pedal rotation,etc.
This may be causing the problem.
I have not changed these tables,no need in my limited experience.
Are you using an adapter between the T/B and manifold?
Is the TAC module grounded?
I`ll post the tune for comparison.
2005 Silverado Mail order F tune.hpt

[scottr126]

Yes I am using an adapter between the TB and intake manifold. The intake is a 4 bolt and the throttle body is 3 bolt so I had to.

Do you mean grounded to the chassis in how its mounted? If-so, no it isn't.

I compared your tune to a good Gen 3 tune.
There are quite a few differences between the two in the ETC ,TPS 1514 areas.
Pedal rotation,etc.
This may be causing the problem.
I have not changed these tables,no need in my limited experience.
Are you using an adapter between the T/B and manifold?
Is the TAC module grounded?
I`ll post the tune for comparison.
2005 Silverado Mail order F tune.hpt

[Earwax]

The TAC is grounded by pin #15 on connector C1.
Blk wire circuit #550 to GND at G104.
G104 is on the back of the motor drivers side near the intake.

[scottr126]

Im tempted to change the Electronic Throttle settings to match the map you posted up but fear this: "WARNING!!! Modify this table at OWN RISK. Incompatibility of this calibration with the vehicle TAC module calibration may render PCM permanently inoperable."

[scottr126]

I will check this tomorrow.

I did check all of the wiring, voltage, and resistances at the TB and it all seemed correct.

The TAC is grounded by pin #15 on connector C1.
Blk wire circuit #550 to GND at G104.
G104 is on the back of the motor drivers side near the intake.

[Earwax]

Did you check the wires from the T/B for poor crimps at the terminals and broken wires?
That is an old bulletin. The wires are usually broken inside the insulation up to 6" or so from the connector.
There is also an old bulletin about the TPS going bad in the T/B.
G103 should be on the rear of the passenger side head.Near the intake.

#PIP3089B: SES Light And Reduced Engine Power DTC P0120 P0220 P1516 P2135 - keywords accelerator actuator APP blade body connector connection DTC L33 L59 LH6 LR4 LM7 LS1 LS2 LQ4 LQ9 module position reduce sensor - (Oct 31, 2006)
Subject: SES Light and Reduced Engine Power DTC P0120 P0220 P1516 P2135

Models: 2004-2006 Buick Rainer
2005-2006 Cadillac CTS-V
2003-2006 Cadillac Escalade
2003-2006 Chevrolet Avalanche, Corvette, Express, Monte Carlo, Silverado, SSR, Suburban, Tahoe, Trailblazer
2003-2006 GMC Envoy, Savana, Sierra, Yukon
2003-2006 Hummer H2
2005-2006 Pontiac GTO
Equipped with a 4.8 5.3 6.0 or 7.0 V-8 Engine
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
A vehicle may be brought into the dealer for a reduced power message, and DTCs P0120, P0220, P1516, P2101, or P2135.

The Throttle Actuator Control (TAC) / throttle body type trouble codes, may be caused by a loose wiring crimp at the throttle body connector, or a broken throttle body circuit.

Recommendation/Instructions:
Complete the current SI diagnostics for any symptoms or trouble codes found. If a intermittent T/P or TAC module type code is occurring complete the inspections below.

Inspect all related throttle body terminals for a loose wiring crimp. The loose crimp may be difficult to find, and the poor connection will be between the terminal and the copper strands of the wire. Wiggle test the individual throttle body circuits to see if the concern can be duplicated.
Inspect the related circuits for broken wires inside the insulation. The outer wire insulation may look fine, but the internal copper strands may be partially broken. Breaks in the wires usually occur within 1 to 4 inches of the throttle body connector. Wiggle testing may also induce a trouble code to set.
On C/K trucks complete SI procedures for voltage drop on grounds G103 and G104. Grounds G103 or G104 may be loose or corroded.
If a terminal crimp or a broken wire has been found, repair or replace only the circuits involved. There is a throttle body pigtail connector available through GMSPO, but installing this pigtail connector may cause other intermittent TAC module/TP codes at a later date. If this pigtail must be used, please follow the SI procedures for Splicing Copper Wire Using Splice Sleeves. (the proper Kent-Moore crimping tool must be used for this repair)

[scottr126]

I will double check the wiring tomorrow. I should probably add the harness is custom made from Current Performance and has maybe 500 miles on it though.

[scottr126]

I checked the grounds and everything is ok.

I have a feeling this may be a software issue?

[Custompowr]

Just had an ecm that wouldn't take throttle an a dbc set up. Changed tune to a known working tune still wouldn't take changed ecm with and put the same known tune in and pesto! I'm new to all this but that was the only thing changed so..... just some food for thought Good luck!

[Earwax]

I agree with following the warnings about changing ETC tables.
Does the TAC,PCM,APP,T/B have any signs of water in the connectors?
Try the tune I posted. It works fine in my 05 truck.
Clear the codes and see what resets.
I would follow the code diagnosis.
Those ETC codes are continuously tested, like every .003 seconds,it should fail just by turning the key on.
Being that it has to run, to fail. May be a poor connection,or a TB-APP issue.
Since the throttle is opened to start, then closes to idle the motor.
Does it set the codes with the key on engine off?

[scottr126]

Well after an evening of trying all kinds of different settings and maps none of that worked.

So finally I pulled up all throttle related channels in Scanner and watched them to see where the code were set, I noticed that once it commanded anything less than 10% the code would be set so I had a feeling it was potentially not closing all the way mechanically.

In the midst of the built I decided against upgrading throttle bodies because I would have to buy the $240 X link adapter on top of the throttle body so I decided to disassemble, clean, and bead blast my ol' truck throttle body so it wouldn't look so hideous on my new Holley intake manifold. Well apparently the throttle plate was installed in a way that it didn't close all the way so I pulled it out flipped it over and IT FIXED IT!!!!!!!!!!

Thanks for all the help guys!