Circuit/System Testing

Ignition OFF, disconnect the harness connector at the T4H Radio Antenna.
Ignition ON, A11 Radio ON.
Verify a test lamp illuminates between T4H Radio Antenna terminal 1 and ground.
- If the test lamp does not illuminate
1. Ignition OFF, remove the test lamp, disconnect the X3 harness connector at the A11 Radio.
2. Test for infinite resistance between the control circuit and ground.
  - If less than infinite resistance, repair the short to ground on the circuit.
  - Go to next step: If infinite resistance
3. Test for less than 2 Ω in the control circuit end to end.
  - If 2 Ω or greater, repair the open/high resistance in the circuit.
  - If less than 2 Ω, replace the A11 Radio.
- Go to next step: If the test lamp illuminates
Ignition OFF, disconnect the X3 harness connector at the A11 Radio. Ignition ON.
Test for less than 1 V between the signal circuit terminal 2 and ground.
- If 1 V or greater
  Repair the short to voltage on the circuit.
- Go to next step: If less than 1 V
Ignition OFF.
Test for infinite resistance between the signal circuit terminal 2 and ground.
- If less than infinite resistance
  Repair the short to ground on the circuit.
- Go to next step: If Infinite resistance
Test for less than 2 Ω between the T4H Radio Antenna signal circuit terminal 2 and the A11 Radio Signal circuit terminal 2 X3.
- If 2 Ω or greater
  Repair the open/high resistance in the circuit.
- Go to next step: If less than 2 Ω
Replace the T4H Radio Antenna.
Ignition ON, A11 Radio ON.
Verify DTC U1264 or U12AB is not set and station reception is normal when tuned to several known good AM and FM stations.
- If DTC U1264 or U12AB is set or AM or FM reception is poor.
  Replace the A11 Radio.
- Go to next step: If DTC U1264 or U12AB is not set and reception is normal.
All OK.