Expert: Roland Finston - 6/29/2011

Question
My Pacifica won't go past 35 mph & is also overheating. Assuming they're separate problems. The odometer shows a p0480 & p0700. The fans won't come on & was wondering if it was the ECT sensor or radiator fan relay? Also if the tranny problem could be related to speed sensor or problem with solenoid? Thanks for any help.

Answer

Hi Shawn,
The 0480 code does point at the radiator fan relay having an issue with the control circuit which includes the actuation coil of the relay, rather than an ECT sensor. You can check the fuse #13 just in case which powers the fans, while the coil of the relay is actuated by the powertrain control module directly when it gets a que from the ect sensor. If that is OK then the relay itself is located on the top of the bumber crossmember, behind the grille. To get to it you would want to remove the panel in the engine compartment that conceals the space between the top of the grille and the radiator, called the radiator closure panel (6 screws/4 pushpins, 2 bolts) and see if that allows you to reach down to disconnect the wire plug, and also remove the rivet that holds the relay in place. You will want to reattach the replacement relay with a fastener to keep it firmly in contact with the crossmemeber for good thermal connection so as to dissipate heat generated in the solid-state relay. If the accessibility is still not good then remove the fasteners that hold the bottom of the grille to the bumper fascia so as to remove the grille entirely.
The 700 code says that there is another fault code stored in the transmission controller that is specific about why you are likely in 'limp' mode as the result, where the transmission for self-protection will only go in 2nd gear and reverse gear. Once the problem is resolved it will go back to normal shifting. To get the other transmission code go to a nationwide autoparts store, such as Autozone where they offer a free readout using a plug-in code reader. Let me know what other code they find (should be in the 0700's or 1700's.
That is how to approach your situation.
Roland
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Roland