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Juan Crespo
Juan Crespo, ASE Certified Technician
Category: Cadillac
Satisfied Customers: 1492
Experience:  A.S.E. Master Technician, Advanced Level, Emissions - Asian, Domestic, & European
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Cadillac Escalade ESV: 2003 escalade esv 6.0 L intermittent

Customer Question

2003 escalade esv 6.0 L intermittent P2135
Submitted: 6 months ago.
Category: Cadillac
Expert:  Juan Crespo replied 6 months ago.
Hi there.In reading your post, I see that you've done most of what GM recommends doing to solve this issue. The one thing I would advise you to double check is the condition of ground points G103 and G104 as those have been shown to be the most probable cause of this issue.Below is the gist of the GM bulletin. I've also attached a graphic showing G103 and G104 for your reference. 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. 1. 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. 2. 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. 3. 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) Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
Customer: replied 6 months ago.
Hi, I've just completed double checking the grounds at G104 and at G103. Nothing found to be out of the ordinary. I had no voltage drop and resistance checked out okay. I did add a ground to pin 15 at the TAC to make sure I wasn't getting an intermittent open. I did not remove/cut the wire just soldered 3 inches away from pin 15. I could not duplicate the problem at this time since it happens every so often. I rechecked TAC data TP1 and TP2 for voltage readings and graphs were perfect. What has me concerned is that while engine is running, pin H at throttle body measures 4.929 volts. At pin E measures 4.296-4.317 volts. If I disconnect the throttle body connector and recheck voltages both pin H/pin E have 5 volts.
Expert:  Juan Crespo replied 6 months ago.
There's something I don't understand regarding your readings at pins E and H; what is it that you're concerned about? Is that voltage discrepancy affecting drivability at this time? How is it idling? How is power on take off and while cruising? Looking at your scan tool screen, do you see any PIDs out of the normal values?
Customer: replied 6 months ago.
I'm concerned about the voltage discrepancy at pin H and pin E which is the 5 volt reference for TP1 TP2. The idle is slightly rough but it has been like that since I've owned the car. Power take off and cruise is normal. I know it's going to be hard to pin point it since it's an intermittent condition. On the scan tool all Pids are within values.
Expert:  Juan Crespo replied 6 months ago.
Thank you for that information.Speaking as a technician, I would say that voltage variation by itself cannot cause a rough idle condition. I would also add that it is also apparently within the allowed parameters since the PCM is not setting a pertinent code.Now, speaking as a retired engineer, it looks like those voltage discrepancies could be the result of the TPS internal resistors not being perfectly calibrated to the specified throttle angle.In conclusion, I'm pretty sure you could actually pinpoint the variation rather easily using a good meter. Problem I see is convincing Cadillac to look for another throttle assembly that has Zero variation, specially when the one that's on your vehicle now shows to be within parameters.Please let me know if there's anything else I can do to help.Best Regards