WTEC III ELECTRONIC CONTROLS TROUBLESHOOTING MANUAL GENERAL DESCRIPTION D. Engine Coolant Temperature Autodetect looks for an engine coolant temperature source during the first 24 engine starts. However, code 26 11 is not logged unless the calibration calls for engine coolant temperature data to be used for retarder capacity reduction or preselect downshifts due to retarder overheating. Autodetect remembers whatever engine coolant temperature source was present on engine start 24. If no analog engine coolant temperature source is found on engine start 24, autodetect concludes that no sensor is present.
Therefore, if an engine coolant temperature is known to be present at engine start 24, but is not detected, troubleshooting of the engine coolant temperature circuit is required. After the engine coolant temperature circuit is repaired, reset autodetect or manually select the engine coolant temperature function using the ATDT TM or Pro-Link ® . 1–11. TRANSID FEATURE A. General Description The TransID feature has been provided so that Allison Transmission can make component changes which require calibration changes but still retain both the original transmission A/N (prior to feature based ordering — FBO) and the original calibrated ECU A/N.
The purpose of TransID is to reduce the need for OEMs to use cross-reference lists of transmission and calibrated ECU A/Ns when such changes to the transmission are made. Since FBO began in April, 1998, the OEM now needs to be sure the ECU being used is compatible with the TransID level stamped on the nameplate of the transmission. The basis for the TransID system is the creation of a TransID wire in the WTEC III system to provide the signal to the ECU of the TransID level of the transmission. This wire will at first be connected directly to the Analog Return (wire 135) to signal TransID level 1 (TID 1).
TransID levels 2 through 8 will then be indicated by connecting the TransID wire in sequence to the return of solenoids A, B, C, D, E, G, and F. Corresponding to the hardware changes is the ability in the V8A and later WTEC III ECU to contain up to eight calibrations. The connection point of the TransID wire will provide the signal to tell the ECU which calibration is required by the transmission. Whenever a TransID level change is to be made, the new TransID level calibrations will be placed in the PROM Calibration Configurator System (PCCS) before the change(s) is (are) made in production to the transmissions.
All ECUs programmed and sold after that date will then be loaded with the new TransID level calibration. These ECUs will contain calibrations for the new level transmission and all previous TransID levels and will automatically load the correct calibration for the transmission based on the TransID signal sensed by AutoDetect during the first twenty-five engine starts. This eliminates worry on the part of the OEM of coordinating the implementation of the new ECU and the new transmission and allows their focus to be on using the stock of the earlier level ECU. B. Transmission Changes Versus TransID Number 1.
TransID 1 The internal wiring harness wiring change to make a TID 1 transmission was put into production before the introduction of the WTEC III system. The TID 1 internal harness was made by connecting the C3 Pressure Switch ground (digital/signal ground; WTEC II wire 161) to the Sump Temperature Sensor and Oil Level Sensor ground (analog ground; wire 135) in the internal harness. In WTEC II, the signal ground wire (wire 161) is routed through the transmission connector, terminal W, and then to the ECU, terminal B27. In WTEC III, this same wire in the internal harness becomes the TransID wire (wire 195), and it goes to the ECU, terminal T13 1–12 Copyright © 2001 General Motors Corp.