DTC U1144 (No. 1144): Lost Communication With Keyless Start Control Module: Troubleshooting

WARNING: This page is about a different car, the 2006 Suzuki Grand Vitara. However, it is still accessible from the selected car via links, so may be relevant.

DTC TROUBLESHOOTING CHART

Step	Action	YES	NO
1	Check DTC in BCM Is DTC U1144 (No. 1144) and DTC U1073 (No. 1073) detected together?	Go to DTC U1073 (NO. 1073): CONTROL MODULE COMMUNICATION BUS OFF .	Go to Step 2.
2	Check DTC in keyless start control module Check DTC for keyless start control module. Is DTC No. 33 detected?	Go to DTC NO. 33: CONTROL MODULE COMMUNICATION BUS OFF .	Go to Step 3.
3	Check each control module connectors Check connection of connectors of all control modules communicating by means of CAN. Recheck BCM for DTC. Is DTC U1144 (No. 1144) detected?	Go to Step 4.	Intermittent trouble. Check for intermittent referring to INTERMITTENT AND POOR CONNECTION INSPECTION .
4	CAN communication circuit check Turn ignition switch to OFF position. Disconnect connectors of BCM and keyless start control module communicating by means of CAN. Check CAN communication circuit between BCM and keyless start control module for open, short and high resistance. Is each CAN communication circuit in good condition?	Go to Step 5.	Repair circuit.
5	DTC check Turn ignition switch to OFF position. Disconnect connectors of all control modules communicating by means of CAN. Connect connectors to BCM and keyless start control module. Recheck BCM for DTC. Is DTC U1101 (No. 1101) detected?	Go to Step 6.	Go to Step 7.
6	DTC Check Turn ignition switch to OFF position. Connect connectors to ECM and ABS and ESP® control module. Check DTC for ECM. Is DTC U0140 detected by ECM?	Substitute a known-good BCM and recheck.	Check keyless start control module power and ground circuit. If circuit is OK, substitute a known-good keyless start control module and recheck.
7	CAN communication circuit check Turn ignition switch to OFF position. Check each CAN communication circuit between disconnected control modules (other than BCM and keyless start control module) for open, short and high resistance. Is each CAN communication circuit in good condition?	Go to Step 8.	Repair circuit.
8	Check DTC in BCM Connect connectors of disconnected control modules communicating by means of CAN. Disconnect connector from any one of control modules other than BCM. Recheck DTC for BCM. Is DTC U1144 detected?	Disconnect connectors of control modules other than the one whose connector is disconnected in Step 2) one by one and check that DTC U1144 is detected by BCM each time connector is disconnected. When DTC U1144 is not detected by BCM while checking in this way, go to description under "NO" below. If DTC U1144 is detected by BCM even when connectors of all control modules that use CAN communication with BCM are disconnected, substitute a known-good BCM and recheck.	Check power and ground circuit of control module disconnect in Step 2). If circuit is OK, substitute a known-good control module disconnected in Step 2) and recheck.