P1220

Code

Other P — Powertrain

Series Throttle Control System Malfunction

Brand: Other

Type: P — Powertrain

Views: UK: 34 EN: 56 RU: 43

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Page language: EN

Causes

Faulty electronic throttle body (throttle actuator/motor)
Defective throttle position sensor (TPS) or pedal position sensor (APP)
Open, shorted, corroded or loose wiring/connectors in throttle control circuits
Low or unstable battery/charging system voltage
Mechanical binding or carbon buildup on throttle plate/linkage
PCM/ECU software fault or internal failure

Symptoms

Check Engine MIL illuminated
Reduced engine power or limp-home mode active
Delayed or no throttle response to accelerator pedal
Erratic idle (high, low or fluctuating)
Surging or engine stalling at low speeds
Possible failure to crank/run if PCM disables throttle control

What to check

Retrieve and record all stored/pending DTCs and freeze-frame data with a scan tool
Check battery voltage and charging system under load (should be ~12.6V resting, 13.5–14.8V charging)
Inspect throttle body and accelerator pedal connectors for corrosion, bent pins, or water ingress
Visually inspect wiring harness for damage, abrasion, or repairs
Use live data to compare accelerator pedal position vs throttle plate position and commanded position
Attempt an electronic throttle actuator test with a bi-directional scan tool (follow OEM procedure)

Signal parameters

Accelerator pedal position (APP) sensor: two or three sensor channels — voltages typically 0.5–4.5 V proportional to pedal travel
Throttle position sensor (TPS) or throttle plate position: voltage typically 0.2–4.8 V corresponding to plate angle
Commanded throttle position (from PCM): percentage 0–100%
Actual throttle position: should track commanded within a few percent and respond promptly
Throttle actuator current or duty cycle: varies with load — should not show continuous maximum current
Battery voltage at PCM/throttle connector during operation: should remain stable above ~11 V under cranking and normal running

Diagnostic algorithm

Step 1 — Verify: Read and record DTC P1220 plus any related codes and freeze-frame data. Clear codes and attempt to reproduce.
Step 2 — Basic electrical: Confirm good battery and charging system voltage. Repair charging/battery issues before further testing.
Step 3 — Visual inspection: Check connectors and wiring at throttle body, APP sensor, and PCM for damage, corrosion or loose pins. Repair as needed.
Step 4 — Live data check: With a scan tool, compare APP sensor outputs with commanded throttle and actual throttle position while an assistant slowly depresses the pedal. Look for mismatches, dropouts or erratic values.
Step 5 — Actuator test: Use a bi-directional scan tool to perform a throttle actuator/motor test to verify movement and response. If actuator does not respond, check supply, ground and control signals.
Step 6 — Voltage/resistance checks: With ignition on, backprobe sensor and actuator pins to verify reference voltages, signal voltages and grounds per OEM values. Check continuity to PCM and for shorts to battery or ground.
Step 7 — Mechanical inspection: With ignition off and following safety procedures, inspect throttle plate for carbon buildup or binding. Clean throttle body if needed and re-test.
Step 8 — Isolate components: If wiring and mechanical checks are good, consider substituting a known-good throttle body or performing PCM bench/scan-tool tests per OEM guidance.
Step 9 — Repair and confirm: Repair or replace faulty parts, clear codes, then road-test and re-scan to ensure P1220 does not return. If intermittent, monitor with extended data logging.
Safety note — Follow OEM safety procedures when performing throttle actuator tests. Prevent unintended vehicle movement and secure the vehicle before tests.

Likely causes

Throttle actuator failure or degraded motor performance
Throttle plate stuck or binding due to carbon deposits
Damaged wiring harness or connector corrosion between throttle body and PCM
Incorrect sensor voltages from pedal or throttle position sensors
Low battery voltage or bad charging system causing control faults

Fault status

⚠️ Status

PCM detected a series throttle control system fault — commanded vs actual throttle or associated circuits out of range; fault stored and vehicle may be in reduced-power mode.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.5-3.0 hours