AEM Error on TPS input
12-13-04, 05:57 PM
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Error on TPS input
Those of you who managed to make the EMS work probably already know this. This information is for anyone new or possibly experiencing problems with getting the EMS to work properly.
When AEM build the pnp EMS, they followed the factory service manual and the circuit diagrams within it. AEM is correct in the pin out assignments, but there is an error in the factory service manual (circuit diagram on page Z-32). According to the service manual diagram, pin 3F (TPS input), pin 3G (TPS WOT input) and pin 3I (+5V ref) is what AEM built into the EMS. But after some pain staking testing, I verified that the circuit diagram had reversed pin 3G and 3F (see the diagram for the actual voltage plot). According to the actual voltage reading pin 3F is the TPS WOT input and 3G is the TPS input.
The actual wiring to the stock ECU is probably correct, the error is in the circuit diagram in the service manual. The WOT input is mainly used for automatic transmission as the gear kick down switch.
There are two ways to correct this problem. The first is to switch pins 3G and 3F at the ECU connector (this would be basically impossible without the factory pin extractor). The second would be to cut the two wires at the TPS connector and x-patch them. The two wires are Green/Red (pin 3F) and Black/Green (pin 3G).
Warning: If you have been trying to tune the EMS without correcting this problem, you will experience odd behavier and strange idle etc.
When AEM build the pnp EMS, they followed the factory service manual and the circuit diagrams within it. AEM is correct in the pin out assignments, but there is an error in the factory service manual (circuit diagram on page Z-32). According to the service manual diagram, pin 3F (TPS input), pin 3G (TPS WOT input) and pin 3I (+5V ref) is what AEM built into the EMS. But after some pain staking testing, I verified that the circuit diagram had reversed pin 3G and 3F (see the diagram for the actual voltage plot). According to the actual voltage reading pin 3F is the TPS WOT input and 3G is the TPS input.
The actual wiring to the stock ECU is probably correct, the error is in the circuit diagram in the service manual. The WOT input is mainly used for automatic transmission as the gear kick down switch.
There are two ways to correct this problem. The first is to switch pins 3G and 3F at the ECU connector (this would be basically impossible without the factory pin extractor). The second would be to cut the two wires at the TPS connector and x-patch them. The two wires are Green/Red (pin 3F) and Black/Green (pin 3G).
Warning: If you have been trying to tune the EMS without correcting this problem, you will experience odd behavier and strange idle etc.
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