P0123: How to Diagnose & Fix — Throttle/Pedal Position Sensor/Switch 'A' Circuit High Input
5 vehicles · 3 makes · $50-$800 repair
How to diagnose and fix P0123: 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) and early T5 engines fails due to internal solder joint cracking from thermal cycling. 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. The issue primarily affects pre-2008 models, as Volvo updated the ETM design. Volvo issued an extended warranty program for the ETM on affected models. 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. Check for Volvo extended warranty coverage, which covered the ETM replacement for up to 10 years on some model years. 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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Ford Edge · 2007–2014
The CD3 Edge uses a Ford electronic throttle body (ETB) with an integrated throttle position sensor. Non-conductive deposits build up on the internal sensor contacts, so the PCM sees an implausible or drifting throttle plate position and drops the vehicle into failsafe/limp mode - the amber wrench warning lights up and engine output is cut to idle-ish power, often at highway speed with no warning. Owners describe it as the truck 'just quitting on me' merging or passing, sometimes clearing after a key cycle and then recurring more frequently. Cleaning the throttle bore does not fix it because the fault is on the electronic contacts inside the sealed unit, not carbon on the plate. Ford acknowledged the family-wide ETB problem with extended coverage programs on several models, and the failure is heavily represented in NHTSA complaints for the Edge.
Common Symptoms
- Amber wrench warning light on the cluster
- Sudden loss of power / limp mode at speed
- Engine will not rev past idle until restarted
- Surging or erratic idle
- Intermittent stall at stops
- Fault clears after key cycle then returns
How to Fix
Replace the throttle body assembly with an updated Motorcraft unit - the internal fault cannot be repaired or cleaned out. Note the part number differs between 2007-2010 and 2011-2014 Edges, so order by VIN. After installation the PCM must relearn throttle position (KAM reset plus an idle relearn drive cycle). Check that the ETB connector and harness pins are not corroded or spread before condemning a second throttle body. Verify whether your VIN falls under any remaining Ford extended service program coverage for ETB before paying out of pocket.
Sources for this issue (4)
- Throttle Body Service or Failure - 3.5L - Ford Edge Forumforum
- Throttle system limp mode issues HELP! - Ford Truck Enthusiasts Forumsforum
- Defective ETBs Are Sending Ford Vehicles into Limp Home Mode - FordProblemsarticle
- P0122 on 2007-2014 Ford Edge: Throttle Body Failure Causes, Symptoms, and Fixesarticle
Jeep Wrangler · 1997–2006
The throttle-body-mounted TPS wears and produces an erratic voltage signal, causing high/hunting idle, stalling at stops, hesitation or bucking on acceleration, and — on automatics — erratic or harsh shifting. A very common, high-search TJ driveability complaint that often illuminates the check-engine light.
Common Symptoms
- High or hunting idle
- Stalling when coming to a stop
- Hesitation/bucking on acceleration
- Erratic or harsh automatic shifting
- Check-engine light
How to Fix
Confirm with a scan tool (P0121/P0122/P0123) and swap in a quality TPS — Mopar 04874371AC (superseded by 68433984AA). Owners strongly recommend Mopar, Standard Ignition, or NGK over cheap economy sensors, which frequently fail again. Verify closed-throttle voltage and idle relearn after install.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Omix 17224.04 throttle-position sensorOEMOmix 17224.04
Replace a circuit-tested TPS on the early throttle-body branch Fitment/availability: 1997-2001 Wrangler TJ 2.5L or 4.0L; verify connector and throttle-body/tang geometry before ordering.
- Genuine Mopar 68404428AA throttle-position sensorOEMMopar 68404428AA
Replace a circuit-tested TPS on the later throttle-body branch Fitment/availability: 2002-2006 Wrangler TJ/Unlimited with 2.4L or 4.0L as cataloged; verify VIN and connector.
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 (2)
Volvo S60 · 2001–2004
Ford Ranger · 2000–2011
Find P0123 by make
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P0123 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 P0123 mean?
P0123 stands for "Throttle/Pedal Position Sensor/Switch 'A' Circuit High Input." This generic code means the PCM detected a higher-than-expected voltage from the throttle position sensor (or accelerator pedal position sensor) 'A' circuit. The computer uses this signal to know throttle/pedal opening for fuel, timing, and electronic throttle control, so an abnormally high reading disrupts those calculations. Symptoms can include erratic idle, hesitation, surging, poor or sudden acceleration, and limp-home mode, making prompt diagnosis important.
What are the most common causes of P0123?
The most common causes of P0123 are: Faulty throttle position sensor, Short to voltage in the TPS signal circuit, Open sensor ground causing high reading, Damaged or corroded TPS connector, Worn throttle body / TPS contacts, Chafed wiring shorting to a power wire, Faulty PCM (rare). The specific cause varies by vehicle.
How much does it cost to fix P0123?
Repair costs for P0123 range from $50 to $800, depending on the vehicle and root cause.
Which vehicles are affected by P0123?
Au7o has documented P0123 across 5 vehicle models from 3 manufacturers: Ford, Jeep, Volvo.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.