With the pinout mapped, Sam traced a faulty crank sensor harness and repaired a corroded connector. The car fired, idled rough for a bit, then settled into a happy purr. On the way to a late-night burger run, Sam thought about sharing the cleaned-up pinout and photos to help other Zexel owners — but first, more testing to make sure their notes matched across engines and years.
If you want, I can draft a template pinout table you can print and fill while you test — tell me the ECU part number or number of connector pins and rows.
Nissan Zexel ECU (commonly found in diesel models like the Patrol, Terrano, and Navara with TD27, RD28, or ZD30 engines) manages the Electronic Fuel Injection (EFI) system. Because Zexel ECUs vary by vehicle year and market, always verify the specific part number on the ECU sticker before wiring. Core Power and Ground Terminals
Before testing sensors, ensure the main supply and ground circuits are intact. Main Ground:
Pin 39 (or Pin 108 on some models) connects directly to the chassis/engine block. Power Supply (+12V): Battery Feed: Pin 105 (Permanent power for memory). Ignition Feed:
Pin 38 (or Pin 93) receives power when the key is in the "ON" position. ECM Relay Control: Pin 4 triggers the main power relay (Self-shutoff control). Critical Sensor Pinouts (Typical ZD30/TD27 Setup)
These pins carry 5V reference signals or varying analog voltages to the ECU. Component / Signal Typical Wire Color Engine Coolant Temp (ECT) Accelerator Pedal Position (APP) Vehicle Speed Signal (VSS) Mass Air Flow (MAF) Sensor Crankshaft Position (CKP) Signal & Ground Charge Air Pressure (Boost) Sensor 5V Sensor Power Supply Red or Orange Sensor Ground (Common) Black/Green Output Control and Actuators
These pins ground the circuit to activate solenoids or relays. Injection Pump Control Unit:
Pins 33, 40, and 53 manage timing and fuel quantity on VP44 Zexel pumps. Glow Plug Indicator: Pin 16 activates the dashboard light. Intake Air Control Valve: Pin 2 controls the solenoid. A/C Relay: Diagnostic and Programming (K-Line) For bench testing or reading fault codes: K-Line (Data): Pin 42 or Pin 88 is used for OBDII communication.
Required for some ECU flash tools; often requires a bridge to a specific point on the PCB to enable "Read/Write" modes. nissan zexel ecu pinout
Nissan Zexel ECU Pinout: A Comprehensive Guide
The Nissan Zexel ECU (Engine Control Unit) is a sophisticated computer system used in various Nissan vehicles to control engine performance, emissions, and diagnostics. For enthusiasts, mechanics, and tuners, understanding the ECU pinout is crucial for modifying, tuning, or troubleshooting the engine. In this article, we'll provide an in-depth look at the Nissan Zexel ECU pinout, its functions, and essential information for working with this system.
What is the Nissan Zexel ECU?
The Zexel ECU is a engine control unit developed by Zexel, a Japanese company that was acquired by Bosch in 1999. The Zexel ECU is used in various Nissan vehicles, including the 300ZX, 350Z, and Skyline models. This ECU is responsible for controlling engine functions such as fuel injection, ignition timing, and emissions.
Nissan Zexel ECU Pinout
The pinout of the Nissan Zexel ECU varies depending on the specific model and year of the vehicle. However, we'll provide a general overview of the common pinouts found in most Zexel ECUs.
Connector Pinout
The Zexel ECU typically has three main connectors: A, B, and C. Here's a breakdown of the pinout for each connector:
Connector A (14-pin)
| Pin # | Signal Name | Description | | --- | --- | --- | | 1 | BAT | Battery voltage | | 2 | GND | Ground | | 3 | IGN | Ignition switch | | 4 | ST | Starter signal | | 5 | FPD | Fuel pump driver | | 6 | INJ | Fuel injector signal | | 7 | IGT | Ignition timing signal | | 8 | CK | Crankshaft position sensor | | 9 | CMP | Camshaft position sensor | | 10 | TPS | Throttle position sensor | | 11 | MAP | Manifold absolute pressure sensor | | 12 | ECT | Engine coolant temperature sensor | | 13 | IAF | Intake air flow sensor | | 14 | GND | Ground |
Connector B (16-pin)
| Pin # | Signal Name | Description | | --- | --- | --- | | 1 | O2S | Oxygen sensor | | 2 | O2H | Oxygen sensor heater | | 3 | EGR | Exhaust gas recirculation valve | | 4 | PCV | Positive crankcase ventilation valve | | 5 | FLC | Fuel level sensor | | 6 | VSS | Vehicle speed sensor | | 7 | NSS | Neutral/park switch | | 8 | WLS | Wide open throttle switch | | 9 | ASL | Air conditioning switch | | 10 | FAN | Cooling fan control | | 11 | INJ | Fuel injector signal | | 12 | IGT | Ignition timing signal | | 13 | ST | Starter signal | | 14 | IGN | Ignition switch | | 15 | BAT | Battery voltage | | 16 | GND | Ground |
Connector C (10-pin)
| Pin # | Signal Name | Description | | --- | --- | --- | | 1 | DIAG | Diagnostic connector | | 2 | CANH | CAN bus high | | 3 | CANL | CAN bus low | | 4 | K-LINE | Communication line | | 5 | L-Line | Communication line | | 6 | VCC | Power supply | | 7 | GND | Ground | | 8 | N/C | Not connected | | 9 | N/C | Not connected | | 10 | GND | Ground |
Functions and Signals
The Nissan Zexel ECU pinout includes various signals and functions, such as:
Working with the Nissan Zexel ECU
When working with the Nissan Zexel ECU, it's essential to have a thorough understanding of the pinout and signal functions. Here are some tips: With the pinout mapped, Sam traced a faulty
| Pin | Wire Color | Signal Name | Description | Spec | | :--- | :--- | :--- | :--- | :--- | | 1 | B/W (Black/White) | Main Relay Control | Activates ECU power relay | Switched ground (12V coil) | | 2 | Lg/W (Lt Grn/White) | Check Engine Lamp (MIL) | To combination meter | Ground to illuminate | | 3 | W (White) | Tachometer Signal | Engine RPM to cluster | 12V square wave | | 4 | G/Y (Green/Yellow) | Injection Timing Control Valve | Regulates hydraulic timing advance | PWM duty cycle (10-90%) | | 5 | L (Blue) | Fuel Cut Solenoid (Stop Solenoid) | Shuts off fuel pump | 12V run / 0V stop | | 6 | B (Black) | Power Ground | High-current ground for drivers | 0V | | 7 | N/C | Not Connected | – | – | | 8 | R (Red) | Battery Backup (Constant 12V) | For ECU memory & clock | 10-14V (always live) | | 9 | B (Black) | Power Ground | Same as Pin 6 | 0V | | 10 | Br (Brown) | Glow Plug Relay Control | Activates glow timer | Ground to engage relay | | 11 | G (Green) | EGR Solenoid Control (if equipped) | Exhaust gas recirculation | 12V PWM | | 12 | L/W (Blue/White) | Cold Start Advance | Solenoid on pump for cold idle | 12V when coolant < 60°C | | 13 | Y (Yellow) | Feedback Fuel Temperature | Fuel temp sensor input | 0-5V | | 14 | P (Pink) | Injection Pump Cam Sensor | Pump position verification | 5V pulse | | 15 | B/R (Black/Red) | Ignition Switch Signal (IG ON) | Main ECU wake-up | 12V with key ON | | 16 | Gr (Gray) | Alternator L-Terminal | Load detection for idle up | 12V when charging | | 17 | Or (Orange) | Data Link Connector (K-Line) | Diagnostic communication (Nissan Consult) | 0-12V variable | | 18 | B/W (Black/White) | Power Ground 3 | Final ground to engine block | 0V |
| Pin | Wire Color | Signal Name | Description | | :--- | :--- | :--- | :--- | | 1 | R (Red) | Battery +12V (Direct) | Main power supply for injector drivers | | 2 | B (Black) | Ground (Engine block) | Heavy ground for output drivers | | 3 | B/R (Black/Red) | Ignition Relay Output | 12V switched after main relay | | 4 | – | Not Used | — | | 5 | Y (Yellow) | Starter Signal (ST) | 12V while cranking | | 6 – 14 | Various | Reserved for ABS/TCS signals on automatic models | Refer to vehicle-specific supplement |
| Pin | Wire Color | Signal Name | Description | Voltage/Spec | | :--- | :--- | :--- | :--- | :--- | | 1 | Lg (Light Green) | TPS Signal 1 | Throttle position sensor main (0-5V) | 0.45V idle / 4.5V WOT | | 2 | Lg/R (Lt Grn/Red) | TPS Signal 2 | Redundant TPS for safety check | Opposite slope of Pin 1 | | 3 | B (Black) | Sensor Ground | Ground for all analog sensors | 0V (chassis) | | 4 | W (White) | Pump TDC Sensor (G) | Top dead center reference for injection | 5V pulse (tooth signal) | | 5 | B/W (Black/White) | Boost Pressure Sensor Signal | Manifold absolute pressure (MAP) | 0.5V (vac) to 4.5V (20psi) | | 6 | Y (Yellow) | Engine Coolant Temp (ECT) | Variable resistance to ground | 2.5V cold / 0.5V hot | | 7 | N/C | Not Connected | – | – | | 8 | R (Red) | +5V Sensor Reference | Powers TPS, MAP, ECT | 5.0V ±0.1V | | 9 | B/P (Black/Pink) | Shield Ground | Drain wire for shielded cables | Chassis ground | | 10 | Or (Orange) | Crank Position Sensor (Ne) | Engine speed & timing | AC sine wave (0.5-5V running) | | 11 | G/B (Green/Black) | Vehicle Speed Sensor (VSS) | From speedometer head | 0-12V square wave | | 12 | Br (Brown) | Intake Air Temp (IAT) | In intake manifold | 2.5V cold / 0.5V hot | | 13 | N/C | Not Connected | – | – | | 14 | W/L (White/Blue) | Accelerator Pedal Full Switch | Idle validation switch | 12V at idle / 0V off idle | | 15 | Lg/B (Lt Grn/Black) | Neutral Position Switch (MT) | Manual trans neutral signal | 0V in neutral / 12V in gear | | 16 | P (Pink) | Clutch Switch Signal | For idle-up on clutch engagement | 12V at rest / 0V depressed | | 17 | Sb (Sky Blue) | Air Conditioner Request | A/C compressor on signal | 12V when A/C ON |
Next Sam traced sensors. With the engine cold, one input rose and fell as the engine warmed; that was coolant temperature (ECT). Another varied smoothly with throttle movement — the throttle position sensor (TPS). Crank and cam signals needed a scope, but a quick test with a timing-light-style pickup when cranking showed pulses on one pin:
Sam noted many Zexel ECUs use hall or inductive pickups for CKP/CMP; voltage levels differ, so they logged voltages and waveform shapes.
Before jumping into the wiring diagram, it is crucial to understand what you are working with. Zexel Corporation was a Japanese manufacturer specializing in fuel injection systems, particularly diesel injection pumps and electronic control units (ECUs).
During the 1990s and early 2000s, Nissan partnered with Zexel to supply ECUs for their off-road and commercial diesel engines. The most common applications include:
Unlike a modern ECU that manages hundreds of parameters, the Zexel ECU in these diesels is primarily a fuel injection control unit. It governs the injection timing, fuel quantity, and cold start advance on inline injection pumps (often Zexel’s own “distributor-type” pumps or “inline” pumps).