A/C Evaporator Air Temperature High
The PCM sources a low current 5 volts on the ACET circuit (this voltage can be measured with the sensor disconnected). As the A/C evaporator air temperature changes, the ACET circuit resistance to SIG RTN (ground) changes (which changes the voltage the PCM detects). When the ACET signal is detected above the self-test maximum, check for open cirucits (ACET or SIG RTN), which would cause the voltage to remain high. Although not as probable, also check for a short to power (VREF).
–Light ON (or Service Engine Soon Warning Light)
P1437 JEEP Description
Indicates the ACET signal input was greater than the self-test maximum. The self-test maximum is 4.5 volts.
JEEP Vehicle:JEEP Commander,JEEP Compass,JEEP Grand Cherokee,JEEP Liberty,JEEP Patriot,JEEP Wrangler,JEEP Wrangler Unlimited,