Power Mac G5, Apple Hardware Test 2.1: Interpreting Certain Error Messages

Symptom

Two error codes in Apple hardware Test (AHT) 2.1 may indicate an error when there is no error:

2FAN/4/x: Fan For BACKSIDE
(The "x" will be a number.)
This error code usually means the fan behind the drive bay has failed. This fan is a "blower" type fan, located behind the drive bay fan. The drive bay fan is located between the hard drive and the SuperDrive.

2FAN/4/x: Fan For SLOT
(The "x" will be a number.)
This error code usually means the slot fan has failed. The slot fan is located in front of the PCI slots near the front of the computer and just under the SuperDrive.

2STH/x/x: xxxx AMB
(The "x" will be a number and "xxxx" will identify a sensor.)
This error code usually means an ambient thermometer sensor has failed.

Solution

When you see "2FAN/4/x: Fan For BACKSIDE" or "2FAN/4/x: Fan For SLOT", there's probably nothing wrong with the fans. To make sure the fans are working:

1. Remove the outer door, leaving the inner air deflector in place.
   
2. Look at the slot fan to see if it is working. (Compare the fan appearance when the computer is turned off, and when the computer is turned on. If the fan "disappears" when the computer is on, it is working.)
   
3. If the fan is not working, take the computer to an Apple Authorized Service Provider for repairs.
   
4. Apple Hardware Test 2.1 has been updated to 2.1.1 and contains a revised fan test. Contact Apple Support to get the updated version.
   
5. When you get the updated Apple Hardware Test, check the fans in your computer to make sure they're working.

When you see "2STH/x/x: xxxx AMB", there's probably nothing wrong with the ambient sensors.

1. Apple Hardware Test 2.1 has been updated to 2.1.1 and contains a revised ambient thermometer test. Contact Apple Support to get the updated version. It is expected to be available by mid November 2003.

2. When you get the updated Apple Hardware Test, check the ambient sensors in your computer to make sure they're working.

If other error codes appear, your computer may need to be repaired. See the AppleCare Service and Support documentation that came with your Power Mac G5 or go to the Apple Support website for service options (http://www.apple.com/support/).