U1121

U1121-LOST COMMUNICATION WITH LIN ECU 1

U1121-Lost Communication With Lin ECU 1:

WHEN MONITORED
With the ignition on.

SET CONDITION
LIN 1 Bus Performance.

POSSIBLE CAUSES
- (D500) LIN BUS circuit open
- (D500) LIN BUS circuit short to ground
- Electronic overhead module
- Cluster

DIAGNOSTIC TEST

1. CHECK FOR AN ACTIVE DTC
Turn the ignition on.
With the scan tool, record and erase DTCs.
Wait 30 seconds.
With the scan tool, read DTCs.

Q: Is the DTC active?

YES: Go To 2
NO: The condition that caused this code to set is not present at this time. Check for an intermittent condition by inspecting the related wiring harness for chaffed, pierced, pinched, and partially broken wires. Also inspect the related connectors for broken, bent, pushed out, spread, corroded, or contaminated terminals.
Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

2. CHECK VOLTAGE AT ELECTRONIC OVERHEAD MODULE




Turn the ignition off.
Disconnect the EOM harness connector.
Turn the ignition on.
Check the voltage of the (A114) Fused B+ (I.O.D.) circuit.

Q: Is the voltage above 10 volts?

YES: Go To 3
NO: Repair the (A114) Fused B+ (I.O.D.) circuit for an open.
Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

3. CHECK GROUND CIRCUIT




Turn the ignition off.
Measure the resistance between ground and the (Z915) Ground circuit.

Q: Is the resistance above 10K ohms?

YES: Repair the (Z915) Ground circuit for an open.
Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Go To 4

4. CHECK LIN BUS CIRCUIT FOR AN OPEN




Disconnect the Cluster C1 harness connector.
Measure the resistance of the (D500) LIN Bus circuit.

Q: Is the resistance below 10K ohms?

YES: Replace the Cluster.
Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Repair the (D500) LIN Bus circuit for an open.
Perform BODY VERIFICATION TEST - VER 1. Body Verification Test