P0120,P0220,P1516 codes Help??

[Cowboy]

Hey dudes when all else fails you guys help me out everytime ty.

I'm having issues and now I dont know where to start. Welp (sigh) here goes. I decided to try a little do it yourself port and polish'n after a so called friend successfully did his sierra. It looks great and was fun and all but when I put it back on... exactly like it came off. I treated it like a flower besides all the grinding and polishing. I smoothed everything out didnt totally remove that little ridge inside @ the bottom front of the TB just knocked it down, didnt go too close to the BFvalve (theres still some discoloration left there. i put it all back together and fired her up and she worked great.

Anyway theres more... the next day I took it back apart to grind off the screw threads on the back of the BF valve (just the part hanging out) and I sharpened the edge of the BF vavle itself (theres still about 1/32 on the edge so i dont think I went to far. I put it all back together and fired it up this time and I see and engine light and the DIC says "REDUCED ENGINE POWER" and the codes are P0120, P0220, and P01516. I didnt drive it, went home the next day and made sure the wires and connector was plugged in to the side of the TB and everything looks good. I'm still getting the codes and dont have a clue. What do i do now? What should I check or do first?

thx for the help

[GasGuzzler]

Most common cause for 120 and 220 are broken wires inside the insulation 1-4" from the T/B connector. Most common cause of 1516 is a weak or dead battery. Also check the ground behind the RH head...black wire with white stripe. Make sure and put your hand on the ring terminal as the wire will break at the end...also the most common rodent chewed wire on a GMT800. If the ground is severed completely there would be no PCM communication and you wouldn't get the codes.

[Cowboy]

thx for the reply

ok I checked the wires, they look good back to the 2nd injector, the ground wire on the head is good and so is the battery. I dont have a voltmeter but I should prolly check the connector?

It wouldnt be a PCM thing since the TB airflow may have changed would it?

I dont get it... any other ideas?

[GasGuzzler]

Did you cut the tape off the harness and pull on each wire, looking for the color to turn white? The copper strands break inside without the colored part breaking. The ground is not on the head, it's behind the intake to the far right of the rear of the valley on the same plane as the oil pressure sender. Don't assume the battery is OK, get it tested.

I did not want to immediately state you ruined the throttle body in the case you had one or more of several common issues but the 1st post makes it sound like you might have.

[txarkitekt]

...and the codes are P0120, P0220, and P01516.

Ok, so you are getting:
P0120 TPS/pedal position sensor a circuit malfunction
P0220 TPS/pedal pos. sensor switch b circuit malfunction
P1516 Throttle Actuator Control aux input

Well, almost 100% of the time, if the TPS or Throttle Actuator gets messed up, it trips all 3 DTCs. As Nathan said, check the wiring. Here is a wiring diagram that might help: Wiring Diagram for TPS

In addition, look at this:

03 Reduced Engine Power - DTCs P0120 , P0220 , P1516 and/or P1518 - 03 Model Year Full Size Trucks and Utilities with 4.8 , 5.3 or 6.0 Engines - kw CEL light low LQ4 LQ9 LR4 MIL reducedpwrmde #PIP3042A - (Aug 30, 2004)

The following diagnosis might be helpful if the vehicle exhibits the symptom described in the PI.

Condition/Concern:

Service Engine Soon Light and / or Reduced Engine Power Mode due to any of the following DTCs: P0120, P0220, P1516 and/or P1518.

Recommendation/Instructions:

If the SI diagnosis and bulletin 03-06-04-032 did not isolate a concern, the following information may help:

1. Inspect the Yellow TAC Motor Control Circuit (581) about 1 inch to 4 inches from the throttle body connector to see if it is broken inside of the insulation.
2. Inspect S102 if there is a P1518 stored. S102 is in the engine harness and is 5.5 inches from the MAP Sensor.
3. Install that latest engine diagnostic calibrations in the PCM. Some 2003 model year vehicles have updated engine diagnostic calibrations available to address DTCs P0120, P0220, P1516 and or P1518. The title of the updated engine diagnostic calibration in TIS2000 is "New calibration to eliminate setting of P0120, P0220, or P1516 with the engine not running. Includes diagnostic enhancements for P1518."

If the above did not help, replace the throttle body and retorque it to 45 lb/in on the 1st pass and 89 lb/in on the second and final pass.

Maybe the wiring got bound up somehow. I would try to disconnect the battery at the negative terminal. Make sure to leave it off for at least 30 minutes. While you are waiting, disconnect the wiring from the TPS and TAC on the throttle body and wiggle the wires around carefully from the connector that plugs into the TB and work you way back about 5" up the wiring harness. Plug it all back in. After 30 minutes, connect negative terminal and restart truck. Did the DTCs go away? If not, head up to Autozone and have them read it. Tell them you replaced the TPS and TAC and just need to have the codes cleared (cause Autozone cannot legally clear them). Once the codes have cleared and if they come back, then either your Throttle Position Sensor or Throttle Actuator is bad.

[GasGuzzler]

Yeah Tyler, that's the bulletin and experience I was sharing. I actually filed a feedback on that document after seeing more than just the yellow wire broken (BTW the yellow and the brown in that bulletin refer to the old school DBW T/B that had an external TPS and different gauge wiring.....the yellow and brown motor control wires were larger than the others) but they wrote back and said there was no reason to change the wording.
Instead, GM wrote a new bulletin and took credit for making the information proper. Look here:

#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)




Here's why I state to look at the battery for P1518 in other topics...

#03-06-04-032: Check Engine Light On with No Driveability Concerns, DTC P0120, P0220, P1516, P1518 (Clear Code) - (Jun 16, 2003)


Subject: Check Engine Light On with No Drivability Concerns, DTC P0120, P0220, P1516, or P1518 Set (Clear Code)


Models: 2003 Cadillac Escalade, Escalade EXT, Escalade ESV

2003 Chevrolet Avalanche, Silverado, Suburban, Tahoe

2003 GMC Sierra, Yukon, Yukon XL

with 4.8L, 5.3L or 6.0L Engine (VINs V, P, T, Z, N, U - RPOs LR4, LM4, LM7, L59, LQ9, LQ4,)
Condition
Some owners may comment that the Check Engine Light is illuminated and there is no driveability concern. Upon investigation, the technician may find codes P0120, P0220, P1516 or P1518. Also, technicians may note that low voltage codes P0562, P0563, P1637 or P1638 have been set.

Cause
The Tach module may set the code in error if it operates at a battery voltage of 4.5 to 5.0 volts.
Correction
If the vehicle has stored one of the low voltage codes, P0562, P0563, P1637 or P1638, follow the appropriate diagnostics for the low voltage code. In most cases, this will lead to correcting the concern without replacing any Electronic Throttle Control (ETC) components.

If codes P0120, P0220, P1516 or P1518 are present without any of the low voltage codes, the technician should observe the Engine RPM in the fault record.

• If the Engine RPM in the fault record is zero and the customer indicates that the vehicles has experienced a low voltage condition, the code should be cleared and the low voltage should be diagnosed and corrected.

• If the Engine RPM is zero and the customer indicates that there have been no low voltage conditions, then the P1516 diagnostic aids for intermittent concerns should be used to diagnose and correct the vehicle

• If the Engine RPM is greater than zero, then check for an obvious loose ground at G103 located next to the right cylinder head just below the head and mounted into the block. Also, check G104 located behind the left cylinder head. Then verify all electrical connections at the TAC module.

[03chevytruck]

Mines been throwing P1518 since Feb. Two trips to the dealership and a dozen other shops, thousands of dollars later and it is still in Reduced Engine Power.
put optima battery.
Dealerdhips replaced throttle body and harness.

[GasGuzzler]

Mines been throwing P1518 since Feb. Two trips to the dealership and a dozen other shops, thousands of dollars later and it is still in Reduced Engine Power.
put optima battery.
Dealerdhips replaced throttle body and harness.

You need help but it needs to be in person by someone smarter than the places you have been.

[Cowboy]

Is it running in the reduced power mode or just the message?

I ended up checking everything you guys had suggested and it was a no go. Everything looked good, i even had the battery checked and it was good. I borrowed a voltmeter and made sure I was getting power to the connector.

The TAC was bad, the sucky part is I dont know how I broke it??

[txarkitekt]

...Well, almost 100% of the time, if the TPS or Throttle Actuator gets messed up, it trips all 3 DTCs. ....

Once the codes have cleared and if they come back, then either your Throttle Position Sensor or Throttle Actuator is bad.

Is it running in the reduced power mode or just the message?

I ended up checking everything you guys had suggested and it was a no go. Everything looked good, i even had the battery checked and it was good. I borrowed a voltmeter and made sure I was getting power to the connector.

The TAC was bad, the sucky part is I dont know how I broke it??

Like what was mentioned above... The Throttle Actuator is a fragile piece once it has been removed. Can't really explain why it gets messed up--just know that it is a high possibility once those codes are thrown.