P2021

Code

Generic P — Powertrain

Intake Manifold Runner Position Sensor/Switch Circuit Low Bank 2

Brand: Generic

Type: P — Powertrain

Views: UK: 28 EN: 66 RU: 40

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Page language: EN

Causes

Faulty intake manifold runner position sensor/switch (Bank 2)
Short to ground in the sensor signal wire or connector
Open circuit or high resistance in wiring or connector (corrosion, broken wire)
Stuck or mechanically seized intake runner or actuator
Faulty actuator or vacuum/boost source that moves the runner
Faulty PCM or poor ground/reference at PCM (less common)

Symptoms

Check Engine Light (MIL) illuminated
Reduced engine power or torque; possible limp-home mode
Rough idle or hesitation under load
Decreased fuel economy
Possible unusual intake noises or sticking sensations from the intake tract

What to check

Read the stored DTC, freeze frame and related/secondary codes (other intake runner or actuator codes)
Use a scan tool to view live data for the intake runner position sensor/switch (Bank 2) while commanding runner positions
Visually inspect the sensor connector and wiring for damage, corrosion, or pins pushed out
Backprobe the sensor connector and measure signal voltage, 5V reference and ground at key pins with ignition on
Manually operate the runner actuator (by hand or with a scan tool/bench test) to verify mechanical movement and observe sensor response
Check continuity and for shorts between the signal wire and ground/other circuits

Signal parameters

Typical sensor type: position potentiometer or position switch; reference = 5 V, signal range approximately 0–5 V (varies by manufacturer)
Low-fault condition: signal voltage near 0 V or fixed low value when circuit should vary with runner movement
Expected behavior: signal should change smoothly as runner/actuator moves between open and closed positions (often ∼0.5–4.5 V)
If switch type: closed = near 0 V or ground when in one position, open = reference pull-up to near 5 V (consult vehicle-specific data)

Diagnostic algorithm

Record the code(s), freeze frame and any related DTCs. Confirm code P2021 is current and not historic.
Inspect the Bank 2 intake runner sensor connector and wiring for damage, corrosion, loose pins or chafing. Repair any obvious issues.
With ignition ON (engine OFF), backprobe the sensor connector: verify 5 V reference, good ground, and monitor signal voltage. Note values and whether signal changes when manually operating the runner/actuator.
Use a scan tool to command the intake runner actuator while observing live signal. If actuator does not move but signal changes, suspect actuator; if actuator moves but signal stays low, suspect sensor or wiring to PCM.
Check continuity from the sensor signal pin to the PCM pin and for short to ground. Repair wiring as required.
If wiring and connector check out, bench-test or replace the sensor/switch (and actuator if applicable). Reinstall and clear codes.
After repair, perform a functional test and road test to confirm proper operation and that code does not return. If fault persists with good wiring and new sensor, consider PCM diagnosis or replacement by qualified technician.

Likely causes

Damaged or corroded connector at the sensor
Wire chafed and shorted to chassis ground near the intake manifold
Sensor internal failure (worn potentiometer or open/shorted switch)
Carbon buildup or mechanical obstruction preventing runner movement

Fault status

⚠️ Status

P2021 — Intake Manifold Runner Position Sensor/Switch Circuit Low (Bank 2). The PCM detects a low or grounded signal from the bank 2 intake runner position sensor/switch. Possible causes include sensor failure, wiring short to ground, poor connector, or mechanically stuck runner/actuator.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours