Ok here we go...alot to digest. I hope it helps you...
P1625:
Alldata doesn't show this, but as yaleronot said, a google search shows Unexpected TCM System Reset
U1000:
DTC U1000 Class 2 Data Link
DTC U1255 Lost Communications
These DTCs set when the control module does not receive a message that it was expecting from another control module, and does not know which control module did not send that message.
1. If the DTC U1000 or U1255 is set in history with other DTCs set current or history, diagnose the other DTCs first.
2. If the DTC U1000 or U1255 set current, this usually indicates a module that is currently not communicating or a configuration issue. For example, if the control module is configured for an option (ie: Onstar, Keyless Entry, Memory Mirrors, etc.) that the vehicle does not have, it may expect to receive a message regarding this missing feature. This would usually occur due to the control module being recently replaced and incorrectly setup.
3. When the DTC U1000 or U1255 is current, the module that is not communicating may not even be listed on the Tech 2 on the Diagnostic Circuit Check/Class 2 Message Monitor list.
4. If the DTC U1000 or U1255 has set in history without other DTCs, replacing the control module setting the DTC is most likely NOT the solution. The module that has set the code is looking for an input from another module that is not communicating. Since the module did not receive an input that it is expecting to see, it sets a U1000 or U1255 which indicates there was a loss of communications. Look at the customer's complaint (ie: intermittent, erratic tachometer operation); this will probably be a better indication of the control module that is the source of the concern. Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition.
See also:
http://i266.photobucket.com/albums/i...ro/U1000-1.gif
http://i266.photobucket.com/albums/i...ro/U1000-2.gif
U1016:
CIRCUIT DESCRIPTION
Modules connected to the class 2 serial data circuit monitor for serial data communications during normal vehicle operation. Operating information and commands are exchanged among the modules. When a module receives a message for a critical operating parameter, the module records the ID number of the module which sent the message for Slate of Health monitoring (Node Alive messages). A critical operating parameter is one which, when not received, requires that the module use a default value for that parameter. Once an ID number is learned by a module, it will monitor for that modules's "Node Alive" message. Each module on the class 2 serial data circuit which is powered and performing functions that require detection of a communications malfunction is required to send a "Node Alive" message every two seconds . When no message is detected from the Powertrain Control Module (PCM) for five seconds , DTC U1016 is set.
CONDITIONS FOR SETTING THE DTC
The ignition is turned to the ON position, and a module on the class 2 serial data circuit does not receive the PCM ID for 5 seconds .
CONDITIONS FOR CLEARING THE DTC
* A current DTC will clear when a "Node Alive" message from the PCM is detected on the class 2 serial data circuit or at the end of the current ignition cycle.
* A history DTC can be cleared with the scan tool.
DIAGNOSTIC AIDS
When multiple Loss of Communication DTCs are set concurrently, the cause is likely to be two opens in the class 2 serial data circuit. Use the Data Link Schematic in order to determine the location of the opens.
See also:
http://i266.photobucket.com/albums/i...lero/U1016.gif
C1226:
CIRCUIT DESCRIPTION
As a toothed ring passes by the wheel speed sensor, changes in the electromagnetic field cause the wheel speed sensor to produce an AC voltage signal. The frequency of the AC voltage signal is proportional to the wheel speed. The amplitude of the AC voltage signal is directly related to wheel speed and the proximity of the wheel speed sensor to the toothed ring. The proximity of the wheel speed sensor to the toothed ring is also referred to as the air gap.
CONDITIONS FOR SETTING THE DTC
DTC C1226 can set when the brake is OFF.
DTC C1226 detects a situation in which the right front wheel acceleration or deceleration is beyond specified limits.
ACTION TAKEN WHEN THE DTC SETS
* A malfunction DTC stores.
* The ABS disables.
* The ABS warning indicator turns ON.
CONDITIONS FOR CLEARING THE DTC
* The condition responsible for setting the DTC no longer exists and the Scan Tool Clear DTCs function is used.
* 100 drive cycles pass with no DTCs detected. A drive cycle consists of starting the vehicle, driving the vehicle over 16 km/h (10 mph), stopping and then turning the ignition OFF.
DIAGNOSTIC AIDS
The following conditions may cause an intermittent malfunction:
* A poor connection
* Rubbed-through wire insulation
* A broken wire inside the insulation
Use the enhanced diagnostic function of the Scan Tool in order to measure the frequency of the malfunction.
If the customer's comments reflect that the amber ABS warning indicator is ON only during moist environmental changes (rain, snow, vehicle wash), inspect all the wheel speed sensor circuitry for signs of water intrusion. If the DTC is not current, clear all DTCs and simulate the effects of water intrusion by using the following procedure:
1. Spray the suspected area with a five percent saltwater solution. Add two teaspoons of salt to twelve ounces of water to make a five percent saltwater solution.
2. Test drive the vehicle over various road surfaces (bumps, turns, etc.) above 24 km/h (15 mph) for at least 30 seconds.
3. If the DTC returns, replace the suspected harness. Thoroughly inspect any circuitry that may be causing the intermittent complaint for the following conditions:
o Backed out terminals
o Improper mating
o Broken locks
o Improperly formed or damaged terminals
o Poor terminal-to-wiring connections
o Physical damage to the wiring harness
Resistance of the wheel speed sensor will increase with an increase in sensor temperature.
Use the following procedure when replacing a wheel speed sensor or harness:
1. Inspect the wheel speed sensor terminals and harness connector for corrosion and/or water intrusion.
2. Replace the wheel speed sensor and jumper harness if evidence of corrosion or water intrusion exists.
TEST DESCRIPTION
4. This test checks the wheel speed sensor for the proper resistance value.
5. This test ensures that the wheel speed sensor generates the proper voltage.
6. This test checks for a short between the wheel speed sensor high and low circuits.
10. This test determines if a wheel speed sensor circuit could be shorted when the EBCM is connected.
See also:
http://i266.photobucket.com/albums/i...ro/C1226-1.gif
http://i266.photobucket.com/albums/i...ro/C1226-2.gif
http://i266.photobucket.com/albums/i...ro/C1226-3.gif