CAR OBD CODES
OBD/DTC Search, e.g.P0120
CAR OBD CODES P0120
P0120 OBD Code Definition:
P0120 Throttle Pedal Position Sensor/Switch A Circuit Malfunction
P0120 OBD Code Description:
OBD2 Code P0120 Definition:
The TPS (Throttle Position Sensor) is a potentiometer that is mounted to the throttle body. It detects the throttle blade angle. As the throttle blade moves, the TPS sends a signal to the PCM (Powertrain Control Module). Usually a three wire sensor: A 5 volt reference from the PCM to the TPS, a ground from the PCM to the TPS, and a signal return from the TPS to the PCM.
The TPS sends the throttle position information back to the PCM on this signal wire. When the throttle is closed the signal is near .45 volts. At WOT (Wide Open Throttle) the TPS signal voltage will approach a full 5 volts. When the PCM sees a voltage that is outside of normal operating range, P0120 will set.
NOTE: The PCM knows that any large change in throttle position means a cooresponding change in manifold pressure (MAP). On some models the PCM will monitor MAP and TPS operation for comparison. Meaning that if the PCM sees a large percentage change in throttle position, it expects to see a cooresponding change in manifold pressure and vice versa. If it doesn’t see this comparitive change, P0120 may set. This doesn’t apply to all models. Symptoms
Possible sumptoms of P0120
Potential symptoms include:
MIL (Malfunction Indicator Lamp) illumination
Misfiring at idle or at highway speed
Poor idle quality
Possibly won’t idle
Possibly starts and stalls
Possible Causes
Possible causes of P0120
Potential causes of the P0120 code include:
Sticking throttle return spring
MAP or TPS connector corrosion
Misrouted harness causing chafing
Bad TPS
Bad PCM
Possible Solutions
If you have access to a scan tool, with KOEO (Key on engine off) observe the TPS voltage. With throttle closed, voltage should be about .45 volts. It should gradually sweep upwards to approximately 4.5 to 5 volts as you depress the throttle. Sometimes only a scope can capture an intermittent glitch in the TPS signal voltage. If you notice a glitch in the TPS sweep voltage, replace the TPS.
NOTE: Some TPS sensors require fine adjustment. If you aren’t comfortable with using a DVOM (Digital Volt Ohm meter) to adjust the new TPS, then it’s best to take the vehicle to a shop. If the voltage is not .45 volts (+or- .3 volts or so) with the throttle closed or if the reading is “stuck” then unplug the TPS connector. With KOEO check for 5 volts reference voltage present at the connector and a good ground. You can check the signal circuit for continuity by jumping a fused wire between the ground circuit of the TPS connector and the signal circuit. If the TPS reading on the scan tool now reads zero, then replace the TPS. However if that doesn’t change the reading to zero, then check for an open or a short on the signal wire and if none is found, suspect a bad PCM. If manipulating the TPS wiring harness causes any change in idle, then suspect bad TPS. OBD-II Codes
P0121 P0122 P0123 P0124
Note: The information on the P0120 error code is purely informative, if you need more useful information, please consult your technician.
B1270 B1203 B2719 B111C B1B62 B295A B009A B29AD B2C92 B25A2 B1780 B2573 B2525 B2616 B1244 OBDII Chassis Codes
C1505 C1847 C1000 C2795 C1729 C1782 C0065 C112D C0055 C2767 C0084 C1102 C0660 C1889 C2792 OBDII Network Codes
U1221 U0183 U0063 U0505 U2601 U1006 U3009 U0428 U0322 U2602 U1142 U2362 U040C U1253 U2615 OBDII Powertrain Codes
P2640 P029A P2234 P0C46 P0786 P0964 P176C P0033 P2273 P1532 P20E7 P0138 P1010 P1791 P0570