P2129
Throttle/Pedal Position Sensor/Switch "E" Circuit Intermittent
- Severity
- Critical
- Driving
- Drive only to a garage
The throttle or pedal position sensor "E" signal is dropping out intermittently. A worn track inside the sensor and a marginal connection produce the same symptom, and the difference matters because one is replaced and the other repaired.
Possible causes
- CommonFailed throttle or pedal position sensor
- CommonCorroded or damaged connector
- CommonWiring damage, particularly at the pedal where feet catch the harness
- CommonLoss of the 5 volt reference or the sensor earth
- PossibleCarbon on the throttle plate affecting the reported position
- PossibleSensor not calibrated after replacement
What you might notice
- Reduced power mode
- Hesitation or surging
- Engine not responding to the pedal
- Rough or unstable idle
- Warning light for reduced engine power
What to check, in order
- Watch all the pedal and throttle position readings together on the live data screen while pressing the pedal slowly through its full travel. The one that jumps, sticks or does not follow the others is the fault.
- Check the reference voltage and earth at the sensor. Several sensors usually share these, so a lost reference produces a scatter of codes from healthy sensors.
- Inspect the connector for corrosion and water, and the harness at the pedal for damage.
- Look for other codes sharing the same reference circuit before condemning this sensor.
- On most vehicles the pedal sensors are part of the pedal assembly and are not supplied separately - establish that before ordering.
Read this code from your own car
Plug an ELM327 adapter into the OBD-II port under the dashboard. Pin16 reads every stored, pending and permanent code, explains each one like this page does — offline, with no account — and shows what the car recorded when the fault was set.
Where this code sits
P00xxP01xxP02xxP03xxP04xxP05xxP06xxP07xxP08xxP09xxP0AxxP0BxxP0CxxP0DxxP0ExxP0FxxP10xxP11xxP12xxP13xxP14xxP15xxP16xxP17xxP18xxP19xxP1AxxP1BxxP1CxxP1DxxP1ExxP1FxxP20xxP21xxP22xxP23xxP24xxP25xxP26xxP27xxP28xxP29xxP2AxxP2BxxP2CxxP2DxxP2ExxP2FxxP30xxP31xxP32xxP33xxP34xxP35xxP36xxP37xxP38xxP39xxP3AxxP3BxxP3CxxP3DxxP3ExxP3Fxx
Fuel and air metering
P2100P2101P2102P2103P2104P2105P2106P2107P2108P2109P2110P2111P2112P2113P2114P2115P2116P2117P2118P2119P2120P2121P2122P2123P2124P2125P2126P2127P2128P2129P2130P2131P2132P2133P2134P2135P2136P2137P2138P2139P2140P2141P2142P2143P2144P2145P2146P2147P2148P2149P2150P2151P2152P2153P2154P2155P2156P2157P2158P2159P2160P2161P2162P2163P2164P2165P2166P2167P2168P2169P2170P2171P2172P2173P2174P2175P2176P2177P2178P2179P2180P2181P2182P2183P2184P2185P2186P2187P2188P2189P2190P2191P2192P2193P2194P2195P2196P2197P2198P2199