Here are the diagnostic procedures. Go through them to see if you can come up with anything.
Btw did you recheck the trouble code to see if it is still the same code?
DTC P1126: THERMOSTAT FUNCTION
NOTE: Using the following diagnostic procedure assumes the presence of a current (hard) DTC or the ability to duplicate the setting of the DTC using DTC confirmation test(s), intermittent recreation procedures or a test drive under conditions stored in freeze frame data.
NOTE: For best results, perform test with ambient temperature at 14 F (-10 C) or more and engine coolant temperature 14-140 F (-10-60 C).
Malfunction is detected when engine coolant temperature does not reach a specified temperature, even though engine has been running for a specified time. Possible causes are:
" Stuck open thermostat.
" Thermostat seal leaking.
" Defective Engine Coolant Temperature (ECT) sensor.
To confirm presence of DTC, replace thermostat using an OEM thermostat. Turn ignition on. Select DATA MONITOR with scan tool and observe engine coolant temperature. Ensure engine coolant temperature is less than 140 F (60 C). Drive vehicle at 50-75 MPH for 10 minutes.
DTC Confirmation Test
Remove ECT sensor. See Fig. 6 . Measure resistance between ECT sensor terminals, with sensor at specified temperatures. See ENGINE COOLANT TEMPERATURE (ECT) SENSOR RESISTANCE table. If resistance is not as specified, replace ECT sensor and retest system. If resistance is as specified, test is complete.
Monday, November 9th, 2009 AT 12:57 PM