Failure to start when warm, High Idle. Throws codes P0128, and P1289

Asked by Jim Nov 02, 2018 at 05:20 PM about the 2003 Mercury Grand Marquis LS Ultimate

Question type: Maintenance & Repair

This problem just occurred yesterday at the local market. It started today cold
when I went to have codes read. I shut the engine off and it wouldn't restart.
Waited 3 hours, still no start.

2 Answers


There are two main causes for P0128: The most common cause is an engine coolant thermostat that has stuck open or is opening prematurely. The next cause is a problem with the engine coolant temperature sensor or the wiring associated with the sensor.


P0129 Possible causes for this code include: Corroded connector face at the MAF/BPS sensor. Insufficient engine vacuum due to engine wear, an ignition misfire or clogged catalytic converter. ... Insufficient system ground at the MAF/BPS. Mass air flow sensor is maf

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