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Holden:Power-train Control Module (view source)
Revision as of 06:32, 9 April 2021
, 06:32, 9 April 2021no edit summary
The '''Power-train Control Module''' or '''PCM''' is the module responsible for management of the engine and transmission.
== 3800 Engines ==
The '''L36''' and '''L67''' 3800-series engines use a single PCM for both engine and transmission management based on the [https://en.wikipedia.org/wiki/Motorola_68HC11 Motorola 68HC11] 8-bit microcontroller. On the majority of L36 and L67 PCMs, firmware, calibration data and software configuration are stored on a single UV-erasable PROM chip within a cartridge inside the PCM. This cartridge is known as the '''Memcal''', and is accessible via a small cover on the PCM held in place by a single screw. Some PCM models however (such as the naturally-aspirated L36 in the VY Commodore) use a non-removable internal flash chip for storage. Flash PCMs have the advantage of being re-programmable via the diagnostic link connector.
[[File:Tpiecm-memcal-removed.jpg|thumb|right|3800 PCM with the Memcal module removed]]
=== Modifications ===
Due to the simplicity of the addressing scheme on the PROM-based PCMs, a number of modifications are possible to enable features commonly found in aftermarket ECUs such as map switching, and realtime tuning. Selecting maps at runtime is possible using techniques such as [https://en.wikipedia.org/wiki/Bank_switching bank switching] on the Memcal itself. This involves using a higher capacity PROM chip, and assigning one or more of the additional address lines, as "switches" to select different memory regions from which the ECU will retrieve data<ref>[https://pcmhacking.net/forums/viewtopic.php?f=11&t=56 pcmhacking.net - EPROM Bank Switching]</ref>.
== LS Engines ==
The Gen III LS engine is managed by a separate ECU based on the [https://en.wikipedia.org/wiki/Motorola_68000 Motorola 68332] 32-bit microcontroller. On VT/VX/VY/VZ Commodores, this ECU integrates with the original 3800 PCM via a separate module, the '''Power-train Interface Module''' or '''PIM'''. Since the Gen III ECU only communicates via CAN bus, the PIM is needed to translate CAN messages into ALDL messages, and vice-versa. The original 3800 PCM is retained for control of the 4L60-E automatic transmission, however engine management functions are disabled via software configuration. Scan tools and other diagnostic equipment communicate with the Gen III ECU directly over CAN bus (exposed on the OBD port using pins 6 and 14).
[[File:Ls1-ecu.jpg|thumb|right|Gen III LS1 ECU]]
== References ==
<references />
== 3800 Engines ==
The '''L36''' and '''L67''' 3800-series engines use a single PCM for both engine and transmission management based on the [https://en.wikipedia.org/wiki/Motorola_68HC11 Motorola 68HC11] 8-bit microcontroller. On the majority of L36 and L67 PCMs, firmware, calibration data and software configuration are stored on a single UV-erasable PROM chip within a cartridge inside the PCM. This cartridge is known as the '''Memcal''', and is accessible via a small cover on the PCM held in place by a single screw. Some PCM models however (such as the naturally-aspirated L36 in the VY Commodore) use a non-removable internal flash chip for storage. Flash PCMs have the advantage of being re-programmable via the diagnostic link connector.
[[File:Tpiecm-memcal-removed.jpg|thumb|right|3800 PCM with the Memcal module removed]]
=== Modifications ===
Due to the simplicity of the addressing scheme on the PROM-based PCMs, a number of modifications are possible to enable features commonly found in aftermarket ECUs such as map switching, and realtime tuning. Selecting maps at runtime is possible using techniques such as [https://en.wikipedia.org/wiki/Bank_switching bank switching] on the Memcal itself. This involves using a higher capacity PROM chip, and assigning one or more of the additional address lines, as "switches" to select different memory regions from which the ECU will retrieve data<ref>[https://pcmhacking.net/forums/viewtopic.php?f=11&t=56 pcmhacking.net - EPROM Bank Switching]</ref>.
== LS Engines ==
The Gen III LS engine is managed by a separate ECU based on the [https://en.wikipedia.org/wiki/Motorola_68000 Motorola 68332] 32-bit microcontroller. On VT/VX/VY/VZ Commodores, this ECU integrates with the original 3800 PCM via a separate module, the '''Power-train Interface Module''' or '''PIM'''. Since the Gen III ECU only communicates via CAN bus, the PIM is needed to translate CAN messages into ALDL messages, and vice-versa. The original 3800 PCM is retained for control of the 4L60-E automatic transmission, however engine management functions are disabled via software configuration. Scan tools and other diagnostic equipment communicate with the Gen III ECU directly over CAN bus (exposed on the OBD port using pins 6 and 14).
[[File:Ls1-ecu.jpg|thumb|right|Gen III LS1 ECU]]
== References ==
<references />