DTC U1290: Climate Control Unit Lost Communication With Seat Heater Control Unit

WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2017 Honda Odyssey, 2016 Honda Odyssey, 2015 Honda Odyssey, 2014 Honda Odyssey, and 2013 Honda Odyssey. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN system diagnosis test mode A (see TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE A ).

Clear the DTCs with the HDS.
Turn the ignition switch to LOCK (0), and then back to ON (II).
Do the Self-Diagnostic Function with the HDS (see HOW TO CHECK FOR DTCS WITH THE HDS ).
Check for DTCs.
Is DTC U1290 indicated?

YES -Go to step 5.

NO -The system is OK at this time. Check for loose wires or poor connections on the seat heater control unit and climate control unit circuit.
Check the No. D20 (7.5 A) fuse in the passenger's under-dash fuse/relay box.
Is the fuse OK?

YES -Go to step 6.

NO -Replace the fuse, and recheck. If the fuse blow again, check for a short in the No. D20 (7.5 A) fuse circuit.
Measure the voltage between seat heater control unit 14P connector terminal No. 9 and body ground.

Fig 1: Measuring Voltage Between Seat Heater Control Unit Connector Terminal And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there battery voltage?

YES -Go to step 7.

NO -Repair an open in the wire between the No. D20 (7.5A) fuse in the passenger's under-dash fuse/relay box and the seat heater control unit.
Turn the ignition switch to LOCK (0).
Disconnect the seat heater control unit 14P connector.
Check for continuity between seat heater control unit 14P connector terminal No. 4 and body ground.

Fig 2: Checking Continuity Between Seat Heater Control Unit Connector Terminal And Body Ground
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Go to step 10.

NO -Check for an open in the wire between the seat heater control unit and body ground. If the wire is OK, check for poor ground at G651 (see RIGHT SIDE WIRE HARNESS (RIGHT FRONT BRANCH) (M) ).
Disconnect climate control unit connector A (28P).

Check for continuity between the following terminals of climate control unit connector A (28P) and the seat heater control unit 14P connector.

CONTINUITY REFERENCE

28P:	14P:
No. 26	No. 11
No. 28	No. 10

Fig 3: Checking Continuity Between Terminals Of Climate Control Unit And Seat Heater Control Unit Connector

Courtesy of AMERICAN HONDA MOTOR CO., INC.

Is there continuity?

YES -Substitute a known-good seat heater control unit, and recheck. If the symptom/indication goes away, replace the original seat heater control unit (see SEAT HEATER CONTROL UNIT INPUT TEST/REPLACEMENT ).

NO -Repair an open in the wire(s) between the climate control unit and the seat heater control unit.