Diagnosis
If there is an open or short circuit to B+ or short circuit to ground for more than 5 minutes, the SID will generate diagnostic trouble code B2371.
| Switch | Function | Voltage (V) | Resistance (Ohms) |
|---|---|---|---|
| VOL | Reduce volume | 1.3 | 78 |
| VOL + | Increase volume | 1.7 | 117 |
| SRC | Selection of audio source | 2.1 | 167 |
| Arrow up | Search forwards | 2.5 | 234 |
| Arrow down | Search backwards | 2.9 | 327 |
| NXT | Preset radio tuning/compact disc | 3.3 | 467 |
| Normal | No button pressed | 4,5 | 2563 |
VOLTAGE AND RESISTANCE CHART
Scheme 1
Scheme 2
Fault symptoms
NO VIN appears in display
Type of diagnosis
Diagnosis is run every time the control module wakes up.
Diagnostic help
Use the diagnostic tool to marry EHU to the car.
See Replacing The Head Unit In The Audio System .
No sound front left.
Continuous.
The voltage level of the output is
- Radio system 1 --> 10V
- Radio system 2/3 --> 3-4V
Test value: Battery voltage
Activation: Speaker test
No sound front right.
Continuous.
The voltage level of the output is
- Radio system 1 --> 10V
- Radio system 2/3 --> 3-4V
Test value: Battery voltage
Activation: Speaker test
No sound rear left.
Continuous.
The voltage level of the output is
- Radio system 1 --> 10V
- Radio system 2/3 --> 3-4V
Test value: Battery voltage
Activation: Speaker test
No sound rear right.
Continuous.
The voltage level of the output is
- Radio system 1 --> 10V
- Radio system 2/3 --> 3-4V
Test value: Battery voltage
Activation: Speaker test
Mute not functioning.
No sound
No sound from telephone/OnStar.
Interference noise when the radio is switched off or in the mute mode.
Clicks from the speakers when switching off the unit.
Continuous when.
Fault in the ignition switch logic of the radio.
It has not been possible to contact SID or EHU.
Continuous.
If there is a diagnostic trouble code stored and it has been read by the diagnostic tool then this indicates that there is an intermittent bus lead fault.
If U0140 and U0194 are stored at the same time then this indicates that it is either the EHU bus lead or a short circuit on the bus that has been the problem. This applies to cars with SDAR.
Fault in the ignition switch logic of the radio.
It has not been possible to contact SDAR or EHU.
No satellite radio sound.
Continuous.
If there is a diagnostic trouble code stored and it has been read by the diagnostic tool then this indicates that there is an intermittent bus lead fault.
If U0140 and U0194 are stored at the same time then this indicates that it is either the EHU bus lead or a short circuit on the bus that has been the problem. This applies to cars with SDAR.
Possibly interference noise or no sound on the satellite radio.
The diagnosis occurs every time the control module wakes and when the EEPROM is programmed.
Possibly no sound from the satellite radio.
It has not been possible to contact SDAR or EHU.
Continuous.
If there is a diagnostic trouble code stored and it has been read by the diagnostic tool then this indicates that there is an intermittent bus lead fault.
If U0140 and U0194 are stored at the same time then this indicates that it is either the EHU bus lead or a short circuit on the bus that has been the problem.
Interference noise or no sound on the satellite radio.
Continuous.
The antenna circuit resistance (cable + antenna) ~160 ohm.
No diagnostic function.
Diagnostic procedure
See BUS AND DIAGNOSTICS COMMUNICATION .
Fault diagnosis procedure is not available.
LOCKED appears in display
Alternative 1: Use the diagnostic tool and marry the EHU with the car.
Alternative 2: Use the diagnostic tool and spare parts program SID and program the VIN number.
Note. The correct VIN number must be stated.
Fault diagnosis procedure is not available.
No satellite radio sound in either the left-hand or the right-hand channel.
Interference noise when the radio is switched off or in the mute mode.
A click is heard from the speakers when the audio system is switched off.
The symptom applies to cars with a separate amplifier.
Poor radio reception.
CD/SDAR functions normally.
Note that a mobile telephone antenna mounted in the glass of the rear window can give impaired radio reception.
One of the following is the likely cause of the fault
- The head unit is not properly pushed into the radio casing.
- Poor connection of the antenna cable in the radio casing/head unit. - Poor connection of the coaxial cable.
- The antenna amplifier voltage supply (trigger voltage) or the ground are incorrect.
- Open circuit in the glass mounted antenna (rear window, 4D or side rear windows, 5D).
- Poor connection between the antenna amplifier and the glass mounted antenna.
Poor radio reception on FM when the electrically heated rear window is on.
Uniform noise level.
Tips for fault diagnosis
Check the electrically heated rear window visually as follows
darken the rear window by covering it with, for instance, a blanket. Switch the electrically heated rear window on and look for sparks on the window.
If a fault is found, repair the rear window with contact paint.
Replace the rear window if necessary.
Fault diagnosis procedure is not available.
No sound from the speakers.
The symptom applies to cars with a separate amplifier.
One of the following is the likely cause of there not being any sound from the speakers
- Faulty lead (trigger) between EHU pin 6 and amplifier pin 12.
To the amplifier
- Blown fuse.
- Faulty voltage supply.
- Faulty ground.
Poor/no satellite radio reception.
Mountains, high buildings, tunnels, parking houses and the like can block the signals which are easily absorbed.
Make sure the car is parked outdoors with nothing blocking the sky southwards. Activate the XM radio on channel 1. If reception is poor, contact XM customer service to verify the customer's account and ask if they are having network problems. If there are no problems with the account or network, check the antenna circuit. See B1259 for fault diagnosis.