Why does my EDC16C34 pinout not match another diagram?

Because the pinout depends on the carmaker’s harness, not on the ECU alone. PSA, Ford and Mazda use the EDC16C34 with different harnesses, and one carmaker can change an assignment with the engine or the model year. A diagram found for another vehicle proves nothing for yours: start from the carmaker’s diagram for your VIN and confirm every pin with a multimeter.

Which pins power an EDC15P+ on the bench?

On the VW Polo three-cylinder TDI documented here, the VW manual and a second source give +12 V on pin 2 (the J317 relay output in the vehicle), terminal 15 on pin 37 and ground on pins 4 and 5. On the bench, feed 2 and 37 from a current-limited, fused supply. On any other application, check the harness first.

How do you find CAN and the K-line without a diagram?

Through the OBD socket, whose pinout is standardized. With the battery disconnected, measure continuity from socket pin 6 to the candidate CAN_H pin, pin 14 to CAN_L and pin 7 to the K-line. A gateway can sit between the engine ECU and the socket, so no continuity does not prove the pin is not a CAN line.

Why is there no MD1CS006 pinout?

Because we found neither a public carmaker diagram nor two independent sources agreeing for a named vehicle. Publishing an unconfirmed list would lead someone to put 12 V on the wrong pin. For this ECU, work from the carmaker’s wiring diagram for your VIN and confirm every pin on the harness before powering anything up.

Do you really need a current-limited supply?

Yes. A battery or an unlimited supply can push tens of amps into a wiring mistake before a fuse reacts, enough to burn a track or an ECU output stage. A current-limited bench supply, plus a fast fuse on every +12 V line, turns a wrong pin into a fault you simply see on the supply display.

Pinout

Bosch ECU pinout: EDC15P+, EDC16C34, MD1CS006

Bosch does not publish the pinouts of its diesel ECUs: pin assignments depend on the carmaker’s harness and vary by vehicle. This page keeps only the supply, ground and diagnostic pins on which two independent sources agree, for a named ECU and a named vehicle application.

By Hugues Orgitello · Updated November 3, 2026 ·

EDC15P+: 121-pin vehicle connector (VAG)

121-pin harness-side connector, VW numbering (T121), taken from a VW Polo three-cylinder unit-injector TDI (J248 control unit, VW part 045906019, sold as an EDC15P+). Assignments vary by application: check your own harness before wiring. The VW manual confirms 6-7 as the CAN pair; which is high (7) and which is low (6) comes from a sibling variant, the EDC15V. On other VW group EDC15 units, CAN can come out on 82 (high) and 83 (low).

Pin	Signal	Dir.	Confirmed application	Agreeing sources	Description
2	+12 V (J317)	In	VW Polo 1.4 l TDI three-cylinder, J248 045906019	VW Polo workshop manual; transpondery.com	+12 V supply from the terminal 30 voltage supply relay (J317); at 0 V with the ignition off (Power)
4	GND		VW Polo 1.4 l TDI three-cylinder, J248 045906019	VW Polo workshop manual; transpondery.com	ECU ground (Ground)
5	GND		VW Polo 1.4 l TDI three-cylinder, J248 045906019	VW Polo workshop manual; transpondery.com	ECU ground (Ground)
6	CAN_L	I/O	VW Polo 1.4 l TDI three-cylinder, J248 045906019	VW Polo manual (6-7 pair); transpondery.com and VW Golf IV EDC15V diagram (polarity)	CAN bus, low line. VW measures the ECU’s internal termination between 6 and 7: 60 to 72 Ω (Differential pair)
7	CAN_H	I/O	VW Polo 1.4 l TDI three-cylinder, J248 045906019	VW Polo manual (6-7 pair); transpondery.com and VW Golf IV EDC15V diagram (polarity)	CAN bus, high line (Differential pair)
37	+15	In	VW Polo 1.4 l TDI three-cylinder, J248 045906019	VW Polo workshop manual; transpondery.com	Terminal 15: switched ignition +12 V (Power)

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Why ECU pinouts change from one vehicle to the next

Bosch sells an ECU platform, not a pinout. Each carmaker sets what every pin does in its own harness: the same EDC16C34 is not wired the same way at PSA, Ford or Mazda, and one VW EDC15 does not share the assignment of another EDC15 on a different engine. There is no public standard and no public Bosch datasheet for these connectors.

Hence the rule on this page: a pin is listed only when two independent sources agree on it for a named ECU and a named application, and each row gives the application and the sources. A forum counts only as confirmation of another source. Everything else is left out on purpose.

What we left out, and why

EDC15P+: the VW manual measures a second supply pin together with pin 2, but it is the only source naming it for this application, so it is not in the table. The K-line and the J317 relay control are documented for other VW group EDC15 variants, not for a named EDC15P+. Pin 2 is fed by the J317 relay, not permanently: no source gives a permanent battery pin for this ECU.

EDC16C34: no pin meets the two-source rule. The supply and ground pins we found for PSA rest on a single tool-vendor diagram, confirmed only by a forum, with no precise application and no certain connector identification; nothing agrees on CAN or the main relay. We found no usable source for the Ford and Mazda 1.6 TDCi EDC16C34 units.

Out of scope on this page, by choice: internal programming points (BDM, JTAG, boot mode), the immobilizer and any change to the emission-control systems.

MD1CS006 (MDG1): no table published

For the MD1CS006, we found neither a public carmaker diagram nor two independent sources agreeing on the supply, ground or diagnostic pins for a named vehicle. We therefore publish no pin for this ECU.

For an MD1CS006, start from the carmaker’s wiring diagram for your vehicle identification number (VIN), then confirm every pin with a multimeter on the harness, as described below.

Confirming on the actual harness

The reference remains the carmaker’s wiring diagram for the exact vehicle. Without it, the diagnostic socket gives reliable starting points, because its pinout is standardized: with the battery disconnected, look for continuity between OBD pin 6 and CAN_H, pin 14 and CAN_L, pin 7 and the K-line. The OBD2 socket pinout gives the other pins.

A ground is confirmed by its resistance to the battery minus terminal: a few tenths of an ohm at most. A supply is confirmed by its voltage, with the ECU connector unplugged: always present for a permanent battery feed, only with the ignition on for terminal 15 or a relay output. On CAN, the resistance between CAN_H and CAN_L with the bus powered off tells you about the terminations; the CAN bus article explains the expected values.

Powering an ECU on the bench without damaging it

Use a current-limited bench supply set to a battery voltage, with a low current limit to start that you raise step by step while watching the current draw. Put a fast, low-rating fuse in series with every +12 V line. Connect the grounds first, then the supplies.

Do not wire anything to a pin missing from these tables or not confirmed on your harness. An ECU power output (injector, solenoid valve, relay) tied to +12 V by mistake can destroy its driver stage. A current draw that hits the limit at once points to a wiring error: switch off and check.

Frequently asked questions

FAQ

Why does my EDC16C34 pinout not match another diagram?: Because the pinout depends on the carmaker’s harness, not on the ECU alone. PSA, Ford and Mazda use the EDC16C34 with different harnesses, and one carmaker can change an assignment with the engine or the model year. A diagram found for another vehicle proves nothing for yours: start from the carmaker’s diagram for your VIN and confirm every pin with a multimeter.
Which pins power an EDC15P+ on the bench?: On the VW Polo three-cylinder TDI documented here, the VW manual and a second source give +12 V on pin 2 (the J317 relay output in the vehicle), terminal 15 on pin 37 and ground on pins 4 and 5. On the bench, feed 2 and 37 from a current-limited, fused supply. On any other application, check the harness first.
How do you find CAN and the K-line without a diagram?: Through the OBD socket, whose pinout is standardized. With the battery disconnected, measure continuity from socket pin 6 to the candidate CAN_H pin, pin 14 to CAN_L and pin 7 to the K-line. A gateway can sit between the engine ECU and the socket, so no continuity does not prove the pin is not a CAN line.
Why is there no MD1CS006 pinout?: Because we found neither a public carmaker diagram nor two independent sources agreeing for a named vehicle. Publishing an unconfirmed list would lead someone to put 12 V on the wrong pin. For this ECU, work from the carmaker’s wiring diagram for your VIN and confirm every pin on the harness before powering anything up.
Do you really need a current-limited supply?: Yes. A battery or an unlimited supply can push tens of amps into a wiring mistake before a fuse reacts, enough to burn a track or an ECU output stage. A current-limited bench supply, plus a fast fuse on every +12 V line, turns a wrong pin into a fault you simply see on the supply display.

Sources

Tables built from these documents and cross-checked against manufacturer datasheets. Always check the datasheet of the connector you actually use: some manufacturers number differently.