P0121: How to Diagnose & Fix — Throttle/Pedal Position Sensor Circuit Range/Performance
12 vehicles · 6 makes · $50-$1,800 repair
How to diagnose and fix P0121: most-reported vehicles
Ranked by owner reports. Each card gives the symptoms, how to confirm the cause, the fix, parts and sources for that vehicle.
Volvo S40 · 2004–2011
The electronic throttle module (ETM) on S40/V50 models with the 2.4L non-turbo (B5244S) engines can fail, setting throttle faults. The ETM controls the throttle blade electronically, and when it fails, the engine enters limp mode with severely limited power or refuses to rev above idle. Volvo's 10-year/200,000-mile Electronic Throttle System warranty extension applied to 1999-2002 P2/P80 models, not to the 2004+ S40/V50. The ETM failure is distinct from the P2 platform (older S60/V70) ETM issue but has similar symptoms.
Common Symptoms
- Check engine light with throttle position codes (P0121, P0122, P0123)
- Engine enters limp mode with limited power
- Engine won't rev above 2,000-2,500 RPM
- Hesitation or surging during acceleration
- Engine stalling at idle
How to Fix
Replace the electronic throttle module (ETM). Updated Volvo part 30711552 or 31216665 depending on engine type. Bosch aftermarket units are also available. Clear fault codes after replacement and perform throttle body adaptation using VIDA diagnostic tool. Note that Volvo's 10-year Electronic Throttle System warranty extension covered 1999-2002 P2/P80 models, not this S40. The repair is straightforward - the ETM bolts to the intake manifold and can be replaced in under an hour.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Volvo 31216327 non-turbo five-cylinder throttle body
replace a scan-data-confirmed internal throttle-body failure on the non-turbo gasoline branch Fitment/availability: Applicable Volvo S40 P1 non-turbo five-cylinder gasoline branch using OE 31216327; confirm VIN, engine code and installed…
- Genuine Volvo 30711552 T5 fuel-injection throttle body
replace a scan-data-confirmed internal T5 throttle-body failure after boost-control and wiring faults are excluded Fitment/availability: Applicable 2004.5-2011 Volvo S40 P1 T5 gasoline branch using OE 30711552; confirm VIN, B5254T engine…
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Sources for this issue (2)
Ford Transit Connect · 2014–2021
Owners report sudden reduced power, poor throttle response, and limp-home behavior due to electronic throttle body contamination/wear or throttle actuator control faults. The issue can be intermittent and may clear after a key cycle, then recur, which is a common pattern in NHTSA complaints and owner reports. It often sets throttle/ETC-related DTCs and can be triggered by carbon buildup or failing throttle position sensing.
Common Symptoms
- Reduced engine power message/limp mode
- Poor throttle response or no acceleration
- Stalling or near-stalling at idle
- Intermittent issue resolved by key cycle
- Check engine light on
How to Fix
Confirm DTCs and perform throttle body inspection/cleaning if contamination is present; if faults persist, replace the throttle body assembly and perform the required idle/throttle relearn procedure. Inspect related wiring/connectors and verify PCM updates if applicable.
Sources for this issue (1)
Volvo S60 · 2001–2002
The 2001-2002 S60 (and other P2 platform Volvos) is notorious for ETM failure due to a design flaw in the throttle body electronics. The module develops internal solder joint cracks and corroded contacts, causing the car to enter limp mode, stall at idle, or refuse to accelerate. Volvo issued an extended warranty covering ETMs up to 10 years/200,000 miles on the 2001 S60 and the non-turbo 2002 S60, but many are now beyond that coverage.
Common Symptoms
- Check engine light with reduced engine power message
- Car enters limp mode (limited to ~30 mph)
- Stalling at idle or low speed
- Rough or surging idle
- Throttle unresponsive or delayed
How to Fix
Replace the ETM unit. Genuine Volvo replacement units have an updated design. Aftermarket options from Bosch are also available. Some specialists offer ETM rebuild services. Always reset the throttle adaptation values after replacement using a Volvo-compatible scanner (VIDA/DiCE).
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- XeMODeX VO.1020 pre-programmed contactless Volvo electronic throttle module
replace a scan-data-confirmed internal early ETM sensor failure with a VIN-preprogrammed contactless unit Fitment/availability: 2001 Volvo S60 Turbo and applicable 2001-2002 S60 non-turbo Magneti Marelli ETM branch; VIN and original-modu…
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
Sources for this issue (4)
Volvo C70 · 1999–2005
Volvo V70 · 1999–2002
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P0121 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0121 mean?
P0121 stands for "Throttle/Pedal Position Sensor Circuit Range/Performance." This code means the throttle position (or accelerator pedal position) sensor's signal does not match what the computer expects compared with other inputs like airflow, RPM, and the second throttle/pedal sensor. The sensor tells the computer how far the throttle or pedal is open; when its range or performance is off, the computer can't trust how much power you're requesting. You may notice hesitation, surging, poor acceleration, rough idle, or the vehicle dropping into a reduced-power 'limp' mode. It indicates an out-of-range or implausible signal rather than a complete loss of signal.
What are the most common causes of P0121?
The most common causes of P0121 are: Worn or failing throttle position sensor, Dirty or carboned-up throttle body affecting plate position, Damaged, frayed, or shorted sensor wiring, Corroded or loose sensor connector, Poor sensor ground or reference voltage, Faulty throttle body / electronic throttle actuator, Mismatch between the two throttle or pedal sensor signals. The specific cause varies by vehicle.
How much does it cost to fix P0121?
Repair costs for P0121 range from $50 to $1,800, depending on the vehicle and root cause.
Which vehicles are affected by P0121?
Au7o has documented P0121 across 12 vehicle models from 6 manufacturers: Cadillac, Chevrolet, Ford, Jeep, Pontiac, Volvo.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.