Fix P0220: Mechanic’s solutions that WORKED

The OBD2 code P0220 indicates an issue with the “Throttle Position Sensor 2 Circuit,” signifying a malfunction in the electrical circuit associated with the throttle position sensor (TPS) 2. This sensor is crucial for informing the vehicle’s powertrain control module (PCM) about the position of the throttle, impacting engine performance, efficiency, and emissions.

P0220 quick overview

Meaning	P0220: Throttle Position Sensor 2 Circuit Malfunction
Is it serious?	Yes, it can lead to engine performance issues, including erratic idle, stalling, and entering limp mode.
Possible causes	– Faulty throttle position sensor – Damaged wiring or connectors in the TPS circuit – Problems with the throttle actuator control (TAC) module – Poor electrical connections or ground issues
How to diagnose?	Inspect the throttle position sensor and wiring for visible damage or wear. Check the electrical connectors at the TPS and TAC module for corrosion or looseness. Perform a wiggle test on the wiring to identify intermittent faults. Test the TAC module and associated circuits for proper operation. Reprogram or replace the PCM if necessary after hardware checks.

How to fix P0220 – learn from mechanics

I looked into P0220 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.

Case #1: GMC

Vehicle information 2003 GMC Sierra 1500 SLE 5.3L

Issue + repair history

• Came in with a code P0220 TP sensor 2 circuit; previously had a P0120 TP sensor 1 circuit
• Throttle body actuator replaced one month ago; throttle body actuator replaced 3 times in the past 3 years
• Updated throttle body electrical connector replaced

Other OBD2 Codes + Test Results

• P0220: Throttle position sensor 2 circuit
• P2135: Throttle position sensor 1-2 correlation
• Test results:
  • TAC module voltage drop test: 0.11 volts

Mechanic suggestions

• Program throttle body replacements with the latest software from the dealer
• Check for broken wires, especially those on the rear of the cylinder heads, ensuring good grounds for proper actuator function
• Check the harness between throttle body and TAC module for intermittent open
• Check connectors at TAC module for water intrusion
• Monitor engine speed when DTC sets; wiggle harness at throttle body and TAC module connectors while observing TAC TP sensor data on the Tech2
• Check grounds G103 and G104, ensuring proper location and tightness
• Perform a reflash of the PCM if all other checks pass

Final fix

• Replaced throttle body unit again, fixing the issue. Vehicle has been running without problems for 2 weeks.

Case #2: Cadillac

Vehicle information 2006 Cadillac CTS V 6.0L

Issue + repair history

• Came in with codes P0220 and P2135
• Throttle body and gas pedal replaced, but MIL lamp still comes on after driving, leading to reduced power mode
• Throttle body replaced again due to return of MIL lamp with code P0222

Other OBD2 Codes + Test Results

• P0220: Throttle body
• P2135: APP circuit 2 fault

Mechanic suggestions

• Perform throttle position relearn and idle relearn after replacing throttle body
• Check for loose wiring crimp or broken throttle body circuit; perform wiggle test on individual throttle body circuits
• Inspect related circuits for broken wires within insulation, particularly within 1 to 4 inches of throttle body connector
• Complete SI procedures for voltage drop on grounds G103 and G104, especially on C/K trucks
• Consider installing an OEM connector at the throttle body with 14-inch wires attached, ensuring all wire is used and soldering connections for reliability
• Check cruise control assembly for looseness, broken wiring, or defects, as APP signals pass through to throttle body assembly
• Refer to TSB PIP3089B for further diagnosis and repair guidance

Final fix

• Replaced throttle body, APP switch, and throttle body connector, resolving the issue.

Case #3: Chevrolet

Vehicle information 2003 Chevrolet Suburban 1500 LS 5.3L

Issue + repair history

• Persistent code P0220 (Throttle position sensor 2 circuit) and P2135 (TP sensor 1+2 disagree or outside performance)
• Throttle position sensor (TPS) replaced multiple times with various units, including Hitachi and AC Delco, sourced from Auto Z.
• Corrosion found on battery negative cable, addressed by replacement.
• No crank issue manipulated by customer due to battery cable issue.

Other OBD2 Codes + Test Results

• P0220: Throttle position sensor 2 circuit
• P2135: TP sensor 1+2 disagree or outside performance

Mechanic suggestions

• Inspect pins at ECM and on harness side, particularly connectors Blue and Red.
• Monitor Ignition 1 voltage parameter with Tech 2; if drops below 10 volts while cranking, replace Ignition 1 Relay.
• Investigate possible loose wiring crimp or broken throttle body circuit; perform wiggle test on individual throttle body circuits.
• Complete SI procedures for voltage drop on grounds G103 and G104, especially on C/K trucks.
• Check bulletin #PIP3089B for bad crimps at terminals.
• Consider replacing throttle body connector and/or throttle body wiring harness.
• Focus on TAC module on the firewall as potential culprit due to common connection for both codes.
• If aftermarket throttle bodies fail repeatedly, try using a used factory part to isolate the issue.
• Consider rewiring from throttle body to TAC module with new wire and terminals at both ends.
• Verify grounds at TAC module, engine block, PCM, and frame; check battery to engine block ground.
• Check wiring harness at throttle body for signs of wear due to engine movement.
• Inspect ground at the back of the intake for rodent damage.
• Replace throttle body entirely from GM dealership if sensor kit replacements prove ineffective.

Final fix

• Throttle body replaced with a used unit, and TAC module replaced, resolving the issue.

Diagnostic Step	Explanation
Inspect TPS and wiring	Look for damage or corrosion that could impair signal transmission.
Check electrical connectors	Ensure connectors are secure and free of corrosion.
Perform a wiggle test	Identify intermittent wiring issues that might not be obvious.
Test TAC module	Verify the module’s functionality, crucial for TPS signal processing.
Reprogram or replace PCM	Update software or hardware to correct issues related to sensor signals.

In these service cases, the troubleshooting process ranged from replacing the throttle body and connectors to addressing wiring issues and updating the vehicle’s software. Each fix was tailored to the specific issues identified during diagnostics, highlighting the importance of thorough inspection and testing to resolve the underlying cause of P0220 effectively.