P218A

Code

Generic P — Powertrain

Throttle Actuator B Control System - Idle Position Not Learned

Brand: Generic

Type: P — Powertrain

Views: UK: 32 EN: 43 RU: 33

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Page language: EN

New or replaced throttle body/actuator or PCM without performing idle relearn
Battery disconnected or low battery voltage during learn cycle
Failed or sticking throttle plate or actuator motor
Faulty throttle position sensor (TPS) or redundant position sensor on actuator B
Wiring harness/connector damage, corrosion, poor pin contact
PCM/ECU software bug or corrupted calibration

Read freeze frame data and full DTC list with a scan tool; note related throttle or voltage codes
Check battery state-of-charge and charging system voltage (during cranking and running)
Visually inspect throttle body B, actuator, wiring harness and connectors for damage or corrosion
Use a scan tool to view real-time throttle position and actuator feedback at key conditions
Confirm whether an idle/closed-throttle relearn has been attempted or is required per service info
Check for recent service that could have cleared learned values (battery replacement, ECU or throttle body replacement)

Battery/charging voltage: normally ~12.0 V (cranking) to 13.5–14.7 V (running); watch for drops during learn
Throttle position/angle (actuator B): should be stable at closed/idle and respond smoothly to commanded changes
Actuator motor command vs feedback: actuator should move when commanded by the scan tool
Redundant position sensors (if present) should agree within manufacturer tolerance
No rapid oscillation or erratic values from TPS at idle

Retrieve DTC P218A and any other stored codes; record freeze-frame and live data.
Verify battery and charging system. Charge battery or perform load test if voltage low. Resolve electrical issues first.
Inspect throttle body B, actuator and connectors for contamination, mechanical binding, foreign objects or damage; clean if contaminated.
Using a manufacturer-capable scan tool, attempt the prescribed idle/closed-throttle relearn/initialization procedure for throttle actuator B. Follow exact OEM steps.
If relearn succeeds, clear codes and perform a road/idle test to confirm the symptom is resolved.
If relearn fails or actuator does not move/respond: monitor actuator command and position feedback with scan tool while commanding movement. Note discrepancies.
Inspect wiring harness continuity and resistance between PCM and actuator (power, ground, signal lines). Repair any breaks, shorts, or corrosion.
If wiring and power are good but actuator or TPS feedback is out of range or nonresponsive, replace the throttle actuator/assembly or position sensor as specified by manufacturer.
After repair or replacement, perform the relearn/initialization procedure and verify via live data that idle position is learned and stable. Clear codes and retest.
If issue persists, check PCM software level and available technical service bulletins (TSBs); reflash or replace PCM only if supported by diagnostics.

Idle relearn procedure was not performed after replacing throttle body or battery
Throttle actuator motor or position sensor fault preventing calibration
Low battery voltage or power interruption while PCM attempted learn
Wiring/connectors between PCM and throttle actuator are damaged or corroded