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Home / DTC / P1220 — Throttle Position (TP) Sensor 2 Circuit

P1220 — Throttle Position (TP) Sensor 2 Circuit

Detailed page for trouble code P1220.

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Code

P1220

CHEVROLET P — Powertrain

Throttle Position (TP) Sensor 2 Circuit

Brand: CHEVROLET
Type: P — Powertrain
AI status
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Page language: EN

Causes

  • Open or short in TP Sensor 2 wiring (signal, reference, or ground)
  • Corroded, loose, or damaged sensor connector
  • Failed TP Sensor 2 (internal fault)
  • Contaminated or sticking throttle body/linkage affecting sensor movement
  • Poor ECM/PCM reference voltage or ground
  • Intermittent wiring damage (chafing, broken conductor)

Symptoms

  • Check Engine Light (MIL) illuminated
  • Reduced power / limp mode
  • Poor or delayed throttle response
  • Inconsistent idle or stalling
  • Unusual throttle behavior during acceleration
  • Diagnostic trouble codes related to TPS or pedal position correlation

What to check

  • Read freeze frame and pending codes; note conditions when P1220 set
  • Scan live TP Sensor 1 and TP Sensor 2 data while slowly opening throttle
  • Visually inspect throttle body connector and wiring for damage or corrosion
  • Perform backprobe voltage checks (reference, signal, ground) at sensor connector
  • Wiggle test wiring while monitoring live data for intermittent faults
  • Check instrument cluster/powertrain grounds and relevant fuses

Signal parameters

  • Reference supply: typically 5.0 V (use scan tool/voltmeter to confirm)
  • Signal voltage (closed throttle): ~0.4–1.0 V (varies by model)
  • Signal voltage (wide open): ~4.0–4.5 V (varies by model)
  • Sensor 2 should track sensor 1 in a consistent linear relationship; large discrepancies or inverted behavior indicate a fault
  • No sudden jumps, drops to 0 V, or voltages above reference rail under normal operation

Diagnostic algorithm

  1. Retrieve freeze frame and additional TPS-related codes; note engine state when stored.
  2. With ignition ON (engine off), backprobe TP Sensor 2 connector: verify 5V reference, ground, and signal presence. If reference or ground missing, trace to PCM/fuse/ground point.
  3. Start engine and monitor live TP Sensor 1 and 2 voltages while slowly opening throttle manually or with pedal. Confirm smooth, proportional change and compare both sensors for correlation (they should rise/track together within manufacturer tolerance).
  4. If signal is stuck, erratic, or out of range, inspect connector and wiring for damage/corrosion; repair or resolder as needed. Perform wiggle test on harness while observing signal.
  5. If wiring and connectors are good, measure sensor resistance if applicable or substitute with known-good TPS to confirm sensor failure.
  6. If sensor and wiring check OK but code persists, inspect throttle body for binding/carbon and clean if required. Relearn throttle/idle adaptations per service manual after cleaning or replacement.
  7. If problem remains after sensor and throttle body service, verify ECM grounds and perform ECM bench/test diagnostics or consider ECM reflash/update as directed by technical service bulletins.
  8. Clear codes and perform road/functional test to confirm repair; monitor for recurrence.

Likely causes

  • Frayed wiring near throttle body or along harness
  • Bent or corroded connector terminals at throttle body
  • Failed potentiometer or Hall-effect element inside TP Sensor 2
  • Throttle body carbon build-up causing sensor to report wrong angle
  • Bad ground at engine/PCM causing noisy/low signal reference

Fault status

⚠️ Status
PCM detected a fault in Throttle Position Sensor 2 circuit (open/short/out-of-range or inconsistent signal).
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-2.5 hours

Similar codes

P0120 P0122 P0123 P0220 P0222 P0223
510

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