Diagnostic Procedure

WARNING: This page is about a different car, the 2005 Jeep Liberty. However, it is still accessible from the selected car via links, so may be relevant.

P1687-NO COMMUNICATION WITH MIC DIAGNOSTIC TEST REFERENCE

TEST	ACTION	APPLICABILITY
1	NOTE: Low fluid level can be the cause of many transmission problems. If the fluid level is low locate and repair the leak then check and adjust the fluid level per the Service Information. NOTE: Always perform diagnostics with a fully charged battery to avoid false symptoms. With the DRBIII®, read Engine DTC's. Check and repair all Engine DTC's prior to performing any transmission symptom diagnostics.With the DRBIII®, read Transmission DTC's. Record all DTC's and 1 Trip Failures. NOTE: Diagnose 1 Trip Failures as a fully matured DTC. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors.Repair as necessary.Perform the Shift Lever Position Test. If the test does not pass, refer to Symptom test for P0706 CHECK SHIFTER SIGNAL .For Gear Ratio DTC's, check and record all CVI's.Most DTC's set on start up but some must be set by driving the vehicle such that all diagnostic monitors have run. NOTE: Verify flash level of Powertrain Control Module. Some problems are corrected by software upgrades to the Transmission and Engine software. NOTE: Check for applicable TSB's related to the problem. Perform this procedure prior to Symptom diagnosis.ContinueGo To 2	All
2	With the DRBIII®, Check the STARTS SINCE SET counter for P1687. NOTE: This counter only applies to the last DTC set. Is the STARTS SINCE SET counter set to zero? Yes --> Go To 3 No --> Go To 6	All
3	With the DRBIII®, check all of the other modules on the vehicle for evidence of a vehicle bus problem. Bus related DTC's in other modules point to an overall vehicle bus problem. Other symptoms such as a customer complaint of intermittent operation of bus controlled features also indicate a bus problem. Does the PRNDL display indicate "No Bus" or is there any evidence of an overall vehicle bus problem? Yes --> Refer to the COMMUNICATIONS CATEGORY and perform the appropriate symptom. Perform 42RLE (NGC) TRANSMISSION VERIFICATION TEST - VER 1 . No --> Go To 4	All
4	Ignition on, engine not running. With the DRBIII®, clear all DTC's. Start the engine in park. NOTE: May take up to 30 seconds of a consistent fault to set this DTC. With the DRBIII®, read the BCM DTC's. Does the Body Control Module have a "MIC MESSAGES NOT RECEIVED" DTC? Yes --> Refer to the COMMUNICATIONS CATEGORY and perform test for "MIC MESSAGES NOT RECEIVED". Perform 42RLE (NGC) TRANSMISSION VERIFICATION TEST - VER 1 . No --> Go To 5	All
5	Ignition on, engine not running. With the DRBIII®, erase Transmission DTC's. Start the engine in park. With the DRBIII®, read Transmission DTC's. Is the DTC "P1687 NO COMMUNICATION WITH THE MIC" present? Yes --> Replace the Powertrain Control Module. WITH THE DRBIII® PERFORM QUICK LEARN . Perform 42RLE (NGC) TRANSMISSION VERIFICATION TEST - VER 1 . No --> Test Complete.	All
6	The conditions necessary to set the DTC are not present at this time. Using the schematics as a guide, inspect the wiring and connectors specific to this circuit. Wiggle the wiring and connectors while checking for shorts and open circuits. With the DRBIII®, check the EATX EVENT DATA to help identify the conditions in which the DTC was set. Were there any problems found? Yes --> Repair as necessary. Perform 42RLE (NGC) TRANSMISSION VERIFICATION TEST - VER 1 . No --> Test Complete.	All