Code
P0222
HUMMER
P — Powertrain
APP (Throttle Position) Sensor 2 Circuit Low Voltage
AI status
Completed
Completed
100%
Causes
- Open or high-resistance wiring on APP sensor 2 circuit
- Short to ground on APP sensor 2 signal wire
- Corroded or loose connector/terminal at the APP module
- Failed APP (accelerator pedal position) sensor/module
- Lost or low 5V reference (VREF) from PCM
- Poor sensor ground
Symptoms
- MIL (Check Engine) lamp illuminated
- Reduced engine power / limp-home mode activated
- Poor or no throttle response to pedal input
- Cruise control disabled
- Unexpected engine behavior during acceleration
- Fault may be intermittent and occur under certain pedal positions
What to check
- Read and record DTCs and freeze frame data with a scan tool
- View live data: APP sensor 1 and APP sensor 2 voltages and compare behavior while operating pedal
- Verify VREF (≈5.0 V) present at APP connector with key ON, engine OFF
- Check sensor ground continuity at APP connector
- Perform visual inspection of pedal module connector and wiring for damage, corrosion, or water
- Backprobe connector while operating pedal to observe voltage changes and correlation between sensor 1 and sensor 2
Signal parameters
- Reference voltage (VREF): ≈5.0 V (key ON, engine OFF)
- Sensor ground: ≈0 V (near chassis ground)
- APP sensor output typical at rest: ~0.5–1.0 V
- APP sensor output typical at full pedal: ~4.0–4.5 V
- Sensors 1 and 2 should track each other — difference normally
- Low-voltage threshold: fault set when sensor 2 voltage drops below expected idle range (often
Diagnostic algorithm
- Connect a capable scan tool; record freeze frame and live APP1/APP2 voltages.
- Key ON (engine OFF): verify VREF ≈5.0 V at APP connector. If VREF missing, check PCM fused circuits and wiring.
- Measure APP sensor 2 signal voltage at rest; expected ~0.5–1.0 V. If low, inspect connector for corrosion, bent pins, or poor contact.
- Backprobe both APP sensor outputs and operate pedal slowly. Confirm APP1 and APP2 voltages increase smoothly and track each other. Note any large discrepancies or sensor2 remaining low.
- If sensor2 is low while sensor1 is normal, disconnect APP connector and measure sensor output at connector; test for short to ground by measuring resistance from signal wire to chassis ground (key OFF). Low resistance indicates short to ground.
- Perform continuity and resistance checks on wiring from APP connector to PCM for opens/shorts; repair any damaged wiring.
- Wiggle the harness and pedal connector while monitoring live data to find intermittent faults.
- If wiring and connectors are good but sensor2 remains abnormal, replace the APP (pedal) module. After replacement, clear codes and test drive to verify code does not return.
- If problem persists with new pedal, inspect PCM input circuits and grounds; consider PCM diagnostics or replacement following manufacturer procedures.
Likely causes
- Damaged/abraded signal wire shorted to chassis ground
- Corroded pins inside APP connector causing poor voltage
- Failed APP sensor 2 inside pedal module
- Intermittent harness connection aggravated by movement
- Low or missing 5V reference due to PCM or fused circuit fault
Fault status
Status
P0222 — APP (Throttle/Accelerator Pedal) Sensor 2 Circuit Low Voltage. PCM detected an abnormally low voltage or poor correlation from APP sensor 2. MIL set; vehicle may enter reduced-power mode.
Repair difficulty: Medium
Diagnostic time: 1.5-3 hours
Similar codes
Repair manuals
Manual library for HUMMER
138
Browse 138 HUMMER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.
HUMMER
-
HUMMER: 2009
-
HUMMER: 2008
-
HUMMER: 2007
-
HUMMER: 2005
-
HUMMER: 2004
-
HUMMER: 2000
-
HUMMER: 1999
-
HUMMER: 1994
-
HUMMER: 1993
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email