U1301

DTC U1301 Class 2 Short To Battery:

DTC U1301 Class 2 Short To Battery (Part 1 Of 2):

DTC U1301 Class 2 Short To Battery (Part 2 Of 2):

CIRCUIT DESCRIPTION
Modules connected to the Class 2 data link monitor the link for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. In addition to this, Node Alive (State of Health) messages are transmitted by each module on the data link about once every two seconds. When the Body Control Module (BCM) and radio receiver detects no messages and a high voltage on the data link for approximately three seconds, U1301 is set and the setting of all other communication DTCs is inhibited.

CONDITIONS FOR SETTING THE DTC
Voltage supplied to the modules are in the normal operating voltage range (approximately 9-16 volts).
^ No valid Class 2 messages are detected on the data link.
^ The voltage level detected on the data link is high.
^ The above conditions are all met simultaneously for three seconds.

CONDITIONS FOR CLEARING THE DTC
^ A current U1301 will clear when a valid Class 2 message is detected on the data link or at the end of the current ignition cycle.
^ A history U1301 will clear upon receipt of a scan tool CLEAR DTCs command.

DIAGNOSTIC AIDS
^ This DTC cannot be retrieved with a current status. Diagnosis of a current U1S01 is accomplished via the symptom, Scan Tool Will Not Communicate With The Class 2 Serial Data Line.
^ An intermittent condition is likely to be caused by a short to voltage on the Class 2 serial data line.

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
1. This test checks whether the lack of communication is due to the scan tool rather than the vehicle.
2. This test checks for a good connection to the power supply ground and battery feed circuits of the DLC.
3. This test checks for battery voltage at the DTC.
4. This test checks for the power supply ground at the DLC.
9. This test checks for a partial malfunction of the Class 2 data link as opposed to total malfunction.
10. This test checks for additional information concerning the location of the malfunction.
13. This test checks for a good connection to the signal ground circuit of the DLC.
14. This test checks for the signal ground at the DLC.
15. This test checks for a good connection to the Class 2 data link circuit of the DLC.
18. This test checks for a short to voltage in the Class 2 data link circuit. The check is made with the key OFF and then with the key ON.
20. Before replacing a module the power and ground circuits need to be checked. This might be the reason the modules can not communicate.
22. This test checks for DTCs in the modules that communicate on the Class 2 data link. These DTCs need to be cleared to avoid future misdiagnosis.