The Throttle Position sensor signals the Engine Control Module as to the current position of the engine throttle valve.
The current throttle valve opening is based on the driver's input from the gas pedal. The ECM uses the information from this sensor to help calculate fuel delivery and spark timing.
Circuit High Input codes like P1991 are mostly caused by defective alternators that develop excessive voltages, although there may be other causes as well, such as short circuits that 'leak' current into a particular system from other, unrelated systems that work on higher voltages. Note that in the case of short circuits that leak power into a control circuit, there is likely to be other, seemingly unrelated trouble codes present along with the code(s) being investigated. Diagnosing a 'high input' code will always involve a thorough testing of the charging system as a first step, followed by measures to isolate the system from all other possible sources of power during resistance, continuity, and reference voltage tests.
Difficulty Level (Easy)
Repair Time (45 Min.)
||Cost Prediction : $ 40-60|
OBD P1991 code and tailpipe testing are two different approaches to identify vehicles in need of repair. The OBD system looks for broken or malfunctioning emissions control components and secondary air injection system switching valve a circuit malfunction, while tailpipe tests sample a vehicle's exhaust to see if it is above or below certain prescribed limits. Given the robust nature of today's emissions control components, it is entirely possible for an individual component to P1991 malfunction without leading to an immediate increase in emissions at the tailpipe. In such cases, other components (like the catalyst) can temporarily compensate for the part that is broken however, these other components can only do double duty for so long before they, too, begin to malfunction. In addition, OBD also monitors for P1991 and other malfunctions in the fuel system problems that traditional tailpipe tests were not designed to identify. Most state and local areas also include a gas cap pressure test as part of an emission inspection.
P1991 is a kind of Powertrain Trouble Code
Powertrain of a modern automobile, comprising engine (with exhaust system), transmission, drive shaft, suspension and the wheels. In a motor vehicle, the term powertrain or powerplant describes the main components that generate power and deliver it to the road surface, water, or air.
You can view according P1991 DTC for your car model. We selected several models to see obd2 solutions click and view it.
|+P1991 Daihatsu Materia||+P1991 Lagonda 12||+P1991 Maserati A6||+P1991 Renault Safrane||+P1991 Ford Interceptor|