INTRODUCTION
PIN VOLTAGE CHARTS are supplied (where available) to speed up the diagnostic process. By checking pin voltages at the electronic control unit, it is possible to determine if the control unit is receiving and transmitting proper voltage signals. Charts may also help determine if control unit harness has shorts or opens.
Note. All voltage tests should be performed with a Digital Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance, unless differently stated in testing procedures.
Note. This ECM voltage chart can be used with a digital voltmeter to help save time in diagnosis. Voltages on the vehicle being tested may vary slightly from these due to battery voltage or alternator charging Level.
THE FOLLOWING CONDITIONS MUST BE MET BEFORE TESTING
- Engine at operating temperature.
- Engine in closed loop operation.
- Engine idling ("Engine Run" column).
- ALDL "test" terminal NOT grounded.
- Scan tester NOT installed.
ECM TERMINAL PIN VOLTAGES (WHITE CONNECTOR)
Note. Terminals not listed are not used or information is not available.
| PIN & (WIRE COLOR) | CIRCUIT NAME | VOLTS: KEY ON | VOLTS: ENGINE RUNNING |
|---|
| W1 (Dk Blue) | Injector Driver | VBAT | VBAT |
| W2 (Lt Green) (3) | A/C Request | 0 | 0 |
| W4 (Gray/Black) | Cruise R/A | N/A | N/A |
| W6 (White) | EST | 0 | 1.1 |
| W7 (Dk Green) | IAC "A" Hi | (4) | (4) |
| W8 (Lt Blu/Wht) | IAC "B" Lo | (4) | (4) |
| W9 (Dk Blue) | IAC "B" Hi | (4) | (4) |
| W10 (Orange) | Battery + | VBAT | VBAT |
| W11 (Gray) | 5V Reference | 5.0 | 5.0 |
| W12 (Tan/Wht) | ECM Ground | 0 | 0 |
| W13 (Blk/Wht) | ECM Ground | 0 | 0 |
| W14 (Blk/Orn) | Sensor Ground | 0 | 0 |
| W15 (Orange) | Battery + | VBAT | VBAT |
| W16 (Pnk/Blk) | Ignition | VBAT | VBAT |
| W17 (Dk Grn/Wht) | IAC "A" Lo | (4) | (4) |
| W18 (Orn/Blk) | P/N Switch | 0 | 0 |
| W19 (Tan/Blk) | Bypass | 0 | 4.5 |
| W20 (Gray) | Cruise Enable | N/A | N/A |
| W21 (Dk Blue) | Cruise Set | N/A | N/A |
| W22 (Dk Grn) | VSS Output/4000 PPM | 0 | 0 |
| W24 (Dk Grn) | Fuel Pump | (5) | VBAT |
| (1) All voltages shown "0" should read less than.5 volt. (2) (Scheme 1)For Connector Terminal Identification (3) A/C, fan "OFF". (4) Not useable. (5) Reads battery voltage for 2 seconds after ignition "ON" then should read 0 volts. |
| (1) | All voltages shown "0" should read less than .5 volt. |
| (2) | (Scheme 1)For Connector Terminal Identification |
| (5) | Reads battery voltage for 2 seconds after ignition "ON" then should read 0 volts. |
ECM TERMINAL PIN VOLTAGES (WHITE CONNECTOR) (1) (2)
ECM TERMINAL PIN VOLTAGES (BLACK CONNECTOR)
Note. Terminals not listed are not used or information is not available.
| PIN & (WIRE COLOR) | CIRCUIT NAME | VOLTS: KEY ON | VOLTS: ENGINE RUNNING |
|---|
| B1 (Orange) | Serial Data | VBAT | VBAT |
| B2 (Purple) | Oxygen Sensor Signal | .1-.55 | .1-.9 |
| B3 (Dk Grn/Wht) (3) | A/C Clutch Relay | VBAT | VBAT |
| B5 (Tan) (4) | IAT Signal | 2.6 | 3.0 |
| B6 (Purple) | VSS Signal (Low) | Varies | Varies |
| B7 (Tan/Blk) | TCC/Shift Light | 0/VBAT | 0/VBAT |
| B8 (Yellow) (4) | CTS Signal | 1.9 | 1.9 |
| B9 (Ppl/Wht) | Ign. Reference Hi | 0 | .9 |
| B10 (Lt Green) | Cruise Vac | N/A | N/A |
| B11 (Dk Blu/Wht) | Cruise Vent | N/A | N/A |
| B12 (Black) | CTS & TPS Ground | 0 | 0 |
| B13 (Yellow) | A/C Signal For Fan | 0 | 0 |
| B14 (Brown) | Cruise/Brake Switch | N/A | N/A |
| B15 (Wht/Blk) | ALDL Diag. Test Term. | 0 | 0 |
| B16 (Blk/Red) | Ignition Ground | 0 | 0 |
| B19 (Dk Blue) | TPS Signal | .6 | .6 |
| B20 (Lt Green) | MAP Signal | 4.8 | 1.1 |
| B21 (Dk Grn/Wht) | Engine Cooling Fan | VBAT | VBAT |
| B22 (Brn/Wht) | "SES" Light | 0 | VBAT |
| B23 (Tan) | 02 Sensor Ground | 0 | 0 |
| B24 (Dk Grn/Wht) | A/C Signal For Fan | 0 | 0 |
| (1) All voltages shown "0" should read less than.5 volt. (2) (Scheme 1)For Connector Terminal Identification (3) A/C, fan "OFF". (4) Varies depending on temperature. |
| (1) | All voltages shown "0" should read less than .5 volt. |
| (2) | (Scheme 1)For Connector Terminal Identification |
| (4) | Varies depending on temperature. |
ECM TERMINAL PIN VOLTAGES (BLACK CONNECTOR) (1) (2)
Scheme 1
