Code
P1511
CHRYSLER
P — Powertrain
Throttle Control System Backup System Performance
AI status
Completed
Completed
100%
Causes
- Faulty electronic throttle body (ETB) or throttle actuator
- Failed or out-of-range accelerator pedal position (APP) sensor(s)
- Intermittent or open/shorted wiring/connectors between APP, ETB and PCM
- Low battery voltage or poor charging system output
- PCM/software fault or corrupted calibration
- Poor ground(s) or corroded connectors
Symptoms
- Malfunction Indicator Lamp (MIL) / Check Engine Light illuminated
- Reduced engine power / 'Limp' mode with limited throttle response
- Fixed or limited idle or throttle position
- Loss of cruise control
- Sudden changes in engine RPM under load or hesitation
- Stored/active DTCs related to throttle, APP sensors, or PCM
What to check
- Read freeze frame and all stored/related DTCs with a capable scan tool
- Check battery voltage and charging system under load
- Inspect wiring and connectors at throttle body, pedal module and PCM for corrosion, damage, loose pins
- Monitor live data: APP1, APP2, throttle position (TP) actual and commanded, motor current, and diagnostic statuses
- Compare APP1 vs APP2 for correlation throughout pedal travel
- Check for technical service bulletins (TSBs) or PCM software updates
Signal parameters
- APP1 voltage: ~0.5–4.5 V (varies by design) — should correlate with APP2
- APP2 voltage: ~0.5–4.5 V — should track APP1
- Throttle plate angle (degrees) — commanded vs actual
- Throttle actuator motor current (A) or motor command duty
- PCM supply voltage (battery) — 12–14.5 V while running
- Diagnostic flags: limp/backup mode active, sensor plausibility flags
Diagnostic algorithm
- Connect a professional scan tool and retrieve all DTCs and freeze frame data. Note whether P1511 is current or historical and any related throttle or APP codes.
- Verify battery voltage at rest and while cranking/running. Charge or replace battery and confirm charging system is healthy before further testing.
- Visually inspect connectors and harnesses at the throttle body, accelerator pedal module, and PCM. Repair any corrosion, bent pins, or damaged insulation.
- With the scan tool, monitor APP1, APP2, commanded throttle, actual throttle, and motor current while slowly pressing the accelerator. Confirm APP sensors correlate and that commanded vs actual throttle follows expected behavior.
- If APP sensors disagree or are out of range, test APP sensor reference, signal and ground circuits with a multimeter per manufacturer specifications. Replace pedal module if faulty.
- If APPs are good but throttle plate does not follow commands, check power/ground to the throttle body and test the actuator motor current and control circuits. Inspect for binding or mechanical restriction.
- Repair any wiring faults and clear codes. Re-test to attempt to reproduce the code under the same conditions.
- If wiring and components test OK but code returns, check for PCM software updates or known issues (TSBs). Reflash or replace PCM only after confirming external components are good.
- After repairs, perform a full system relearn/calibration procedure if required by the manufacturer and verify normal operation and absence of P1511.
Likely causes
- Corroded/loose connector at throttle body or pedal module
- APP sensor pair disagreement (APP1 vs APP2) or out-of-range signal
- Throttle actuator motor current or position feedback abnormal
- Low vehicle voltage during drive cycle triggering backup strategy
- PCM has internal fault or requires software reflash
Fault status
Status
Throttle Control System - Backup System Performance: PCM detected backup/fallback throttle control behavior or backup performance outside expected parameters, often causing reduced power/limp mode.
Repair difficulty: Medium
Diagnostic time: 1.0 - 3.5 hours
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