P2021 – Intake Manifold Runner Position Sensor/Switch Circuit Low Bank 2 (OBD2)
P2021 means "Intake Manifold Runner Position Sensor/Switch Circuit Low Bank 2". The voltage the control unit measures in the intake manifold tuning valve circuit is below the permitted minimum. For a sensor this usually means the signal wire is shorted to ground or the reference voltage is missing; for an actuator, that its control wire is shorted to ground.
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P2021 quick summary
| Fault code | P2021 |
|---|---|
| Meaning | Intake Manifold Runner Position Sensor/Switch Circuit Low Bank 2 |
| System | Powertrain (Engine & Transmission) |
| Vehicles | Generic OBD2 |
| Severity | Low |
| Can I drive? | Yes. You may notice slightly less power at certain engine speeds. |
| Repair cost | €20 – €600 |
How the intake manifold tuning valve works
The intake manifold tuning valve changes the length or path of the intake runners to improve torque at low rpm and power at high rpm; these codes cover its control circuit.
Many petrol engines have a variable intake manifold: a flap or valve switches between long runners (more torque at low rpm) and short runners (more power at high rpm). It is operated by a vacuum actuator controlled by a solenoid, or by an electric motor with a position sensor.
Codes P0660–P0665 report open, low or high faults in the tuning valve control circuit for bank 1 and bank 2. If the valve does not switch, the engine loses some torque or top-end power, but usually runs normally otherwise.
Typical causes are a failed solenoid, cracked vacuum hoses, a sticking flap or broken linkage, and wiring problems.
Bank 2 is the cylinder row that does NOT contain cylinder 1, so this code only appears on V6, V8, V10, V12 and boxer engines.
Symptoms of P2021
- Check Engine light on
- Reduced power at low or high rpm
- Rattle from the intake (broken linkage)
- Slightly higher fuel consumption
- Often no noticeable symptoms
Most common causes of P2021 (most likely first)
Mechanic's Pro Tip
On many engines the plastic linkage of the intake flaps breaks long before the actuator fails – look at the linkage before buying a new actuator.
1.Signal or control wire shorted to ground
Most likelyLook for chafed insulation where the harness touches the engine, exhaust brackets or body edges.
2.Missing 5 V reference or supply voltage
An open reference wire or a shorted sensor elsewhere on the same reference circuit can pull it down.
3.Internal short in the intake manifold tuning valve
4.Failed tuning valve solenoid or actuator
5.Cracked vacuum hose
6.Sticking flap or broken linkage
7.Wiring or connector fault
Step-by-step diagnostic guide
- 1
Read codes
Read all codes and note which bank is affected.
- 2
Measure the signal voltage
With the ignition on and the intake manifold tuning valve plugged in, back-probe the signal wire. Then unplug it and check the reference/supply and ground wires separately.
Multimeter: Signal near 0 V = short to ground or no reference. Reference wire: about 5 V with ignition on. Signal wire to ground with connector unplugged: no continuity.
- 3
Command the valve
Use the scan tool to switch the valve and watch or listen for movement.
- 4
Check vacuum and solenoid
Check the vacuum supply and hoses; measure the solenoid resistance.
Multimeter: Many tuning valve solenoids read about 20–40 Ω; check the specification.
- 5
Check the linkage
Check that the flap moves freely and the linkage is intact.
- 6
Repair and verify
Replace the faulty part and clear the codes.
Frequently asked questions
Can I keep driving with P2021?
Yes. You may notice slightly less power at certain engine speeds.
How much does it cost to fix P2021?
Typical repair costs are 20 € – 600 €, depending on the cause and the vehicle. The most common fixes are: signal or control wire shorted to ground; missing 5 V reference or supply voltage; internal short in the intake manifold tuning valve. Always confirm the cause with the tests above before buying parts.
Is an intake manifold tuning valve code serious?
Usually not; the engine loses some performance but runs normally.
Is it the same as swirl flaps?
Similar but not the same: tuning valves change the runner length, swirl flaps change the air flow pattern in the cylinder. Some engines have both.
What is the difference between P2021 and similar codes?
P2021 belongs to a group of codes for the same component that differ in the type or location of the fault: P2017 – Intake Manifold Runner Position Sensor/Switch Circuit High Bank 1; P2018 – Intake Manifold Runner Position Sensor/Switch Circuit Intermittent Bank 1; P2019 – Intake Manifold Runner Position Sensor/Switch Circuit Bank 2; P2020 – Intake Manifold Runner Position Sensor/Switch Range/Performance Bank 2; P2022 – Intake Manifold Runner Position Sensor/Switch Circuit High Bank 2; P2023 – Intake Manifold Runner Position Sensor/Switch Circuit Intermittent Bank 2. The tests on this page apply to the whole group; the type of fault tells you where to start.
Related fault codes
- P2020Intake Manifold Runner Position Sensor/Switch Range/Performance Bank 2
- P2022Intake Manifold Runner Position Sensor/Switch Circuit High Bank 2
- P2023Intake Manifold Runner Position Sensor/Switch Circuit Intermittent Bank 2
- P2019Intake Manifold Runner Position Sensor/Switch Circuit Bank 2
- P2018Intake Manifold Runner Position Sensor/Switch Circuit Intermittent Bank 1
- P2017Intake Manifold Runner Position Sensor/Switch Circuit High Bank 1
- P2016Intake Manifold Runner Position Sensor/Switch Circuit Low Bank 1
- P2015Intake Manifold Runner Position Sensor/Switch Range/Performance Bank 1
This guide is for information only. Working on vehicles can be dangerous — if you are unsure, have the car checked by a qualified mechanic. Values can differ between model years; always check the manufacturer's repair information.