P1299 is a very common Ford-only trouble code. It indicates that your Mercury Grand Marquis has entered “Cylinder Head Overtemperature Protection”, which is a fail-safe mode designed to keep it from overheating so much that the engine gets damaged. It is known to appear BEFORE the temp gauge or warning light alerts you to an … Read more
P0730 is a standard OBD2 trouble code. It indicates that your Mercury Grand Marquis’s PCM has detected an incorrect gear ratio. While this code can appear if you changed your Grand Marquis’s transmission or rear end gearing without re-flashing the computer, it almost always has nothing to do with an incorrect gear ratio. An internal … Read more
P0871 is a somewhat rare diagnostic trouble code. While your Mercury Grand Marquis’s check engine light will come on, this particular code indicates that there’s something wrong with the transmission, specifically the transmission fluid pressure sensor switch “C”. It’s a generic code, so P0871 has the same definition for any vehicle made for the 1996 … Read more
P0480 is a relatively common OBDII trouble code. It indicates that your Mercury Grand Marquis’s “cooling fan 1 control circuit” is malfunctioning. It’s a generic code, so it has the same meaning for any vehicle made for the 1996 model year and up. P0480 Definition: Cooling Fan 1 – Control Circuit Malfunction Here is … Read more
P0320 is a relatively common ignition-related trouble code. P0320 indicates that your Mercury Grand Marquis’s ignition/distributor engine speed circuit is malfunctioning. P0320 is most likely caused by the engine speed sensor, or a wiring issue. P0320 Definition: Ignition/Distributor Engine Speed – Input Circuit Nearly all modern vehicles, including the Mercury Grand Marquis, use individual coil … Read more
P0717 is a somewhat rare OBD2 trouble code that can occur in the Mercury Grand Marquis. While it illuminates the check engine light, the code warns of a transmission-related error, specifically that the input shaft/turbine speed sensor is not sending a signal. P0717 is a generic code (it has the same meaning for any vehicle … Read more
P0601 is a somewhat rare OBD2 trouble code. It’s a generic code (it has the same meaning for the Mercury Grand Marquis as it would any other vehicle). While it indicates that the PCM’s memory failed a memory check, P0601 is commonly seen when people use OBD2 port plugin accessories on their vehicle. These accessories … Read more
P0846 is a relatively common trouble code. While your Mercury Grand Marquis’s check engine light will come on, P0846 is a transmission-related trouble code, specifically the transmission fluid pressure sensor circuit. It’s a generic code, so P0846 has the same definition for any vehicle made for the 1996 model year and up. Before doing anything, … Read more
P0841 is a relatively common trouble code. While your Mercury Grand Marquis’s check engine light will come on, this particular code indicates that there’s something wrong with the transmission, specifically the transmission fluid pressure sensor circuit. It’s a generic code, so P0841 has the same definition for any vehicle made for the 1996 model year … Read more
P0882 is a generic DTC trouble code, which means it has the same meaning for the Mercury Grand Marquis as it would any other vehicle. While this code sets the check engine light, it is actually warning you of an issue with the TCM transmission control module, specifically that the power input signal is too … Read more