Quad-Driver Check (Except 3.1L & 4.3L Turbo)
- Remove ECM from vehicle. Using DVOM on 100/200 k/ohm scale, measure resistance between ECM case and each ECM quad-driver terminal. Touch negative DVOM lead to case and positive lead to ECM terminal. See appropriate ECM QUAD-DRIVER TERMINAL IDENTIFICATION table.
- Each terminal should have at least 50 k/ohms resistance. If all quad-driver terminals have greater than 50 k/ohms resistance, go to step 4). If any terminal has less than 50 k/ohms resistance, locate driven component(s) for the quad-driver with the lowest resistance. Disconnect component from circuit and check circuit for short to voltage.
- If circuit is not shorted to voltage, replace component before replacing ECM to prevent recurring ECM failure. See appropriate ECM QUAD-DRIVER TERMINAL IDENTIFICATION table.
- Using a fused ammeter capable of measuring at least 2 amps, turn ignition on with engine off. Connect one lead of ohmmeter to chassis ground. Connect remaining lead to each ECM harness quad-driver circuit. Measure each circuit for sustained current flow for at least 2 minutes.
NOTE:
TCC solenoid cannot be easily tested for current draw, since completed circuit depends upon internal transmission oil pressure switches.
- If no circuit has more than .75 amp sustained current flow, replace ECM. If any circuit has more than .75 amp sustained current flow, check for short to voltage in that circuit. If short to voltage is not present, replace related solenoid or relay.
ECM QUAD-DRIVER TERMINAL IDENTIFICATION (2.5L)
| QDR No. |
ECM Terminal |
Component |
| 1 |
A2 |
Shift Light (M/T) |
| 1 |
A2 |
TCC Solenoid (A/T) |
| 1 |
A4 |
A/C Relay |
| 1 |
A5 |
SES Light |
| 1 |
C1 |
Not Used |
| 2 |
A3 |
EGR Solenoid |
| 2 |
A7 |
Not Used |
| 2 |
C2 |
Not Used |
| 2 |
D12 |
Not Used |
ECM QUAD-DRIVER TERMINAL ID (2.8L W/O 4L80-E TRANS)
| QDR No. |
ECM Terminal |
Component |
| 1 |
A2 |
A/C Relay |
| 1 |
A3 |
Not Used |
| 1 |
C1 |
Not Used |
| 1 |
C2 |
EAC Solenoid |
| 2 |
A4 |
EGR Or EVRV Solenoid |
| 2 |
A5 |
SES Light |
| 2 |
A7 |
TCC Solenoid (A/T) |
| 2 |
A7 |
Shift Light (M/T) |
ECM QUAD-DRIVER TERMINAL ID (3.8L W/ 4T60-3 TRANS)
| QDR |
PCM Terminal |
Component |
| A |
GC4 |
Cooling Fan (Low Speed) |
| A |
GC5 |
Purge Solenoid |
| A |
GC6 |
TCC Solenoid |
| B |
GC15 |
TCC PWM Solenoid |
| B |
GD15 |
Shift Solenoid "B" |
| B |
GD16 |
Shift Solenoid "A" |
ECM QUAD-DRIVER TERMINAL ID (4.3L CPI W/O 4L80-E TRANS)
| QDR No. |
ECM Terminal |
Component |
| 1 |
A2 |
TCC Solenoid (A/T) |
| 1 |
A4 |
Not Used |
| 1 |
A5 |
SES Light |
| 1 |
C1 |
Not Used |
| 2 |
A3 |
EGR Control |
| 2 |
A7 |
Intake Tuning Valve |
| 2 |
C2 |
Not Used |
| 2 |
D12 |
Not Used |
ECM QUAD-DRIVER TERMINAL ID (4.3L TBI & V8 W/O 4L80-E TRANS)
| QDR No. |
ECM Terminal |
Component |
| 1 |
A2 |
Not Used |
| 1 |
A3 |
Not Used |
| 1 |
C1 |
Not Used |
| 1 |
C2 |
EAC Solenoid |
| 2 |
A4 |
EGR Or EVRV Solenoid |
| 2 |
A5 |
SES Light |
| 2 |
A7 |
TCC Solenoid (A/T) |
| 2 |
A7 |
Shift Light (M/T) |
| 2 |
B4 |
Not Used |
ECM QUAD-DRIVER TERMINAL ID (ALL WITH 4L80-E TRANS)
| QDR No. |
ECM Terminal |
Component |
| 1 |
A2 |
Shift Solenoid B |
| 1 |
A3 |
Shift Solenoid A |
| 1 |
A4 |
TCC Solenoid |
| 2 |
A7 |
SES Light |
| 3 |
A11 |
EGR Or EVRV Solenoid |