2003 Dodge Caravan engine code P1698

DTC P1698: NO BUS MESSAGE FROM TRANS CONTROL MODULE
NOTE:For component location, see COMPONENT LOCATIONS. For connector identification, see CONNECTOR IDENTIFICATION. For circuit identification and wiring diagram, see WIRING DIAGRAMS. In testing procedures Alpha/Numeric character in parenthesis i.E. (K4) designates circuit. After each repair procedure has been completed, reconnect all components. Perform POWERTRAIN VERIFICATION TEST VER-1 under VERIFICATION TESTS to ensure system is functioning properly.

Monitored & Set Conditions
Messages from Transmission Control Module (TCM), when equipped with a 4 speed automatic transmission, are monitored with ignition on and battery voltage greater than 10.4 volts. DTC will set if no bus messages are received from TCM for 20 seconds on 2 trips.
Possible Causes
Intermittent Condition
Communication With TCM
PCM

Turn the ignition on. With the DRBIII Â scan tool, erase DTCs. Cycle the ignition key on and off several times, leaving the ignition on for at least 20 seconds. With the DRBIII Â scan tool, read DTCs. Does the DTC reset? If yes, go to next step.

With the DRBIII Â scan tool, attempt to communicate with the TCM. Can communication be established with the TCM? If yes, go to next step. If no, perform the appropriate test related to no communication with TCM.
WARNING:When the engine is operating, do not stand in a direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing.

The conditions that set the DTC are not present at this time. The following may help in identifying the intermittent condition. With the engine running at normal operating temperature, monitor the DRBIII Â scan tool parameters related to the DTC while wiggling the wiring harness. Look for parameter values to change and/or a DTC to set. Review the DRBIII Â scan tool Freeze Frame information. If possible try to duplicate the conditions under which the DTC was set.
Visually inspect the related wiring harness.
Look for any chafed, pierced, pinched, or partially broken wires. Visually inspect the related wiring harness connectors. Look for broken, bent, pushed out, or corroded terminals. Were any of the above conditions present? If yes, repair as necessary. If no, test is complete.

Suspect the transmission is going out, the sensor pick up on the difference between the input and out shafts not correlating becasue the internal clutches are slipping.

This is a common problem with these vans.

Please let us know happens so it will help others.

Best, Ken

P1698 - No Bus Message From TCM

Why did you replace the computer? First I'd erase the code and see if it comes back. If it does, start by checking the fuses. If it doesn't, any chance the ignition switch was turned on while no computer was plugged in?

Code 700 in the Engine Computer just means there's a code in the Transmission Computer. Most simple code readers don't access anything other than the Engine Computer. You need a scanner to read the codes in the other computers.

When a computer detects a problem, it sets a fault code. It's important to read those codes before a computer or the battery is disconnected, otherwise that valuable information will be lost. That's especially important when you're trying to find the cause of an intermittent problem. Without a code to start with, diagnosing the cause of a problem is almost impossible.

The original computer should not have been replaced just because it stored a fault code. The computers themselves really don't cause many problems. If you still have the original one, stick it back in, then hope it detects the same problem so it can be identified.

What was the original symptom? Code 700 should have turned on the Check Engine light, but was there a shifting problem too?

Hi JAKESNAKE,

This code means the main computer is having a problem, I would try disconnecting the wiring connectors at the PCM and checking them for corrosion, if none is found this is a classic computer failure. Replace the computer and then retry the system and can get a used one from a wrecker to save money too.

No ccd message from PCM. Check wiring and pins where the wiring plugs into the PCM. Make sure they are tight, no pins are pushed in, and there is no corrosion.

Hi:
The P1698 code means that no digital data is being received by the powertrain controller (on the left inner fender) from the transmission control module, located on the right inner fender.

If you are mechanicaly inclined and have worked on car electrical systems, the manual says to check the ccd bus wires between the module and the rest of the system using the Chrysler diagnostic readout box. But if you don't have one, I think you can do the same thing by measuring for continuity (near 0 resistance) between pin 4 of its plug and pin 11 of the data link plug under the dash.

Next, check the resistance between pin 43 if its plug and pin 3 of the data link connector. Finally check continuity from pin 7 of the data connector and pin 65 of the powertrain connector (pink wire). If the continuity between the transmission and data link connector wires checks as well as from the connector to the PCM proves to be ok, then according to the manual the trans controller should be replaced. Additionally, you should also verify that there is either a + or - bias voltage of 2.5 volts on each of those wires as a loss of bias voltage will also cause this code.

Let me know if this helps.
Joe