HOW-TO: TPS Tester/ECU Code Light

[Phoenix7]

Thanks to TeamFC3S for the info.



To build the tester you will need the following parts (or equivalents) available from Radio-Shack:

• 2 units of Red LED Lamp Assembly, Cat. No. 276-011a. These are red LED's that looks like regular 12V lamp indicators and can be mounted in a 21/64 (8.3mm) diameter hold.
• 2 units of Male Quick Disconnects (10), Cat. No. 64-3038a. Each of these bags contain 10 assorted spades, among them 4 non-isolated and 2 isolated 0.25" spades. We highly recommend to use isolated spades to prevent short circuit between the spades when connecting them to the Diagnostic Connector. This is why you need two units to have the three 0.25" spades we need for the tester.

Figure 1. Parts needed


These components are pretty standard and compatible ones are available from various sources. If you can't get them from Radio-Shack, try any automotive store for the spades and an electronic supplier for the LED assemblies (Digikey might be a good candidate, and their full catalog is available on-line). If you can't get a LED assembly with built-in current limiting resistor, you can build them them from scratch as described in the diagram below. The resistor can be of any value from 330 to 1000 ohm. We recommend to use a 510 ohm resistor that will result in current of about 20 ma through the LED. The diode is used to protect the LED from reverse voltage in case the tester is connected improperly. Any diode such as 1N4001 with a breakdown voltage of 25V or more and maximal current of 100 ma or more will protect the LED just fine.


Figure 2. LED Schematics with Reverse Voltage protection

The construction of the tester is very simple, just follow these two easy steps:

1. Connect together the two anodes to a spade (use a crimping tool if you have one) . This will be ABR lead.
2. Connect each of the cathodes to a spade. These leads will be DCC1 and DCC2 respectively.

Figure 3. Completed Tester.

To check the tester, connect the ABR lead to the (+) post of the battery and connect the DCC1 lead to ground. Make sure that the DCC1 LED lit. Repeat the step for the DCC2 lead. If the test was OK, you are ready to test it using the ECU itself. First turn the ignition switch OFF. Then insert the three spades of the tester to the ABR, DCC1 and DCC2 pins of the diagnostic connector. Make sure you connected the right spades to the right pins. Turn the ignition switch ON (you don't have to actually start the engine) and watch the two LED's. They should be on for about 3 seconds and then will go off. If any error code exists, one or two of the LED's will periodically flash. The next section contains a detailed description of how to interpret the flashes and determine what the error codes are.

[Phoenix7]

Thanks to TeamFC3S for the info.



To build the tester you will need the following parts (or equivalents) available from Radio-Shack:

• 2 units of Red LED Lamp Assembly, Cat. No. 276-011a. These are red LED's that looks like regular 12V lamp indicators and can be mounted in a 21/64 (8.3mm) diameter hold.
• 2 units of Male Quick Disconnects (10), Cat. No. 64-3038a. Each of these bags contain 10 assorted spades, among them 4 non-isolated and 2 isolated 0.25" spades. We highly recommend to use isolated spades to prevent short circuit between the spades when connecting them to the Diagnostic Connector. This is why you need two units to have the three 0.25" spades we need for the tester.

Figure 1. Parts needed


These components are pretty standard and compatible ones are available from various sources. If you can't get them from Radio-Shack, try any automotive store for the spades and an electronic supplier for the LED assemblies (Digikey might be a good candidate, and their full catalog is available on-line). If you can't get a LED assembly with built-in current limiting resistor, you can build them them from scratch as described in the diagram below. The resistor can be of any value from 330 to 1000 ohm. We recommend to use a 510 ohm resistor that will result in current of about 20 ma through the LED. The diode is used to protect the LED from reverse voltage in case the tester is connected improperly. Any diode such as 1N4001 with a breakdown voltage of 25V or more and maximal current of 100 ma or more will protect the LED just fine.


Figure 2. LED Schematics with Reverse Voltage protection

The construction of the tester is very simple, just follow these two easy steps:

1. Connect together the two anodes to a spade (use a crimping tool if you have one) . This will be ABR lead.
2. Connect each of the cathodes to a spade. These leads will be DCC1 and DCC2 respectively.

Figure 3. Completed Tester.

To check the tester, connect the ABR lead to the (+) post of the battery and connect the DCC1 lead to ground. Make sure that the DCC1 LED lit. Repeat the step for the DCC2 lead. If the test was OK, you are ready to test it using the ECU itself. First turn the ignition switch OFF. Then insert the three spades of the tester to the ABR, DCC1 and DCC2 pins of the diagnostic connector. Make sure you connected the right spades to the right pins. Turn the ignition switch ON (you don't have to actually start the engine) and watch the two LED's. They should be on for about 3 seconds and then will go off. If any error code exists, one or two of the LED's will periodically flash. The next section contains a detailed description of how to interpret the flashes and determine what the error codes are.