HughesTech Labs: Our Engineering group has been working on a 2004 Dodge Grand Caravan SE 3.3L that would go into the famous Chrysler Limp Mode after triggering the Scan Codes P0700 P1776. Our Engineering group was pretty sure the codes had nothing to do with the Power-train Control Module (PCM), nor the Low Reverse Solenoid in the Valve Body! After Many hours of research (internet searches, Forums), the group found that everyone having the same scan codes for 2003 – 2007 Dodge Caravans, Dodge Grand Caravans, and 2003 – 2007 Chrysler Town & Country Minivans were being told they needed major Transmission work.
STOP Right Here! Don’t Spend A Dime Yet!
Update: Another cause discovered
Long story short, our Engineers found that the scan codes p0700 p1776 were actually very miss-leading as the Transmission was overheating! Our Engineer’s biggest complaint were why Chrysler would not have installed a Temperature Sensor in the Transmission and report the correct code!
It seems Chrysler/Dodge use a computer calculation to determine the temperature of the transmission fluid!
How you can check to see if your scan codes p0700 p1776 are caused by overheating:
1).. check that your Radiator Fans are coming on when told to by the Power-Train Control Module (PCM).
Hint, when the A/C is on (A/C Compressor running) both Radiator Fans should be on!
If they are not, then you need to find the Radiator Relay Module and take some voltage readings.
Below we included a diagram showing the Location of Radiator Fan Relay Module in the 2004 Dodge Grand Caravan:
What we are about to tell you, you do at your OWN RISK we will not be held responsible for the actions of others!
Our Engineers removed the connector from the Radiator Fan Relay Module and rerouted it out along side of the Driver’s side Headlight so that they could add a jumper wire to two (2) pins within the connector. Using a #14 solid copper with plastic coating (such as used for home electrical wiring) wire three (3) inches long and stripped 1/2 inch (.5″) at both ends, inserted this jumper wire into the Radiator Fan Relay Module socket where the large RED wire and Large Blue wire connect to. This allows both fan motors to come on full-speed!
Next they test drove the Dodge Grand Caravan after resetting the Engine Light (MIL Scan code) with the scan tool.
They did get an Engine Light code po480 which was only reporting about the Radiator Fan Relay Module and this scan code would not put the Transmission into the “Chrysler Get Me Home Mode” or “Limp Mode” so their test could continue.
The test was a success, the Power-Train Control Module (PCM) never sent the scan codes p0700 p1776 again!
Just as they thought it was not a Transmission problem after all and those scan codes p0700 p1776 were bogus!
The root cause of the fan motors not coming on was a bad radiator, soon as the pressure would build in the radiator the fluid would come out through holes in the core until there was not enough coolant left in the system to give the Temperature Sensor located behind the Thermostat a correct reading!
This Temperature Sensor is the one used along with the ambient air-flow Sensor to calculate when to turn on the Fan motors.
Our Engineers Replaced the Radiator and Coolant with new and connected the Fan Relay Module backup and the Minivan is good for another 100,000 miles!!!!!
So before you spend thousands of dollars for a new Transmission, follow the steps above and see if the Dodge/Chrysler Transmission is actually the problem or some other fault!
This may also be the same problem on other Dodge/Chrysler products showing the same scan codes! We don’t know that as we were focused on the Minivans
Hope that this post helps others with the same problems!