DTC P0627-P0629
Diagnostic Instructions
DTC Descriptors
| DTC P0627 00: Fuel Pump Relay Control Circuit
Open |
| DTC P0628 00: Fuel Pump Relay Control Circuit
Low Voltage |
| DTC P0629 00: Fuel Pump Relay Control Circuit
High Voltage |
Diagnostic Fault Information
Circuit
|
Short to Ground
|
Open/High Resistance
|
Short to Voltage
|
Signal Performance
|
Relay Coil Control
|
P0628 00
|
P0627 00
|
P0629 00
|
-
|
Relay Coil Ground
|
-
|
-
|
-
|
-
|
|
| |
Circuit/System Description
The engine control module (ECM) provides ignition voltage to the
coil side of the fuel pump relay whenever the engine is cranking or
running. The ECM enables the fuel pump relay as long as the engine
is cranking or running, and ignition system reference pulses are
received. If no ignition system reference pulses are received, the
ECM turns OFF the fuel pump. The fuel pump relay control circuit is
equipped with a feedback circuit that is pulled up to voltage
within the ECM. The ECM can determine if the control circuit is
open, shorted to ground, or shorted to a voltage by monitoring the
feedback voltage.
Conditions for Running the DTC
P0627 00 and P0628 00
| • |
The power stage is not
active. |
| • |
The DTCs run continuously once
the above conditions are met. |
P0629 00
| • |
The ignition is ON, or the
engine is running. |
| • |
The power stage is
active. |
| • |
The DTCs run continuously once
the above conditions are met. |
Conditions for Setting the DTC
P0627 00
The ECM detects the fuel pump relay control circuit is open for
greater than 1 s.
P0628 00
The ECM detects the fuel pump relay control circuit is shorted to
ground for greater than 1 s.
P0629 00
The ECM detects the fuel pump relay control circuit is shorted to
battery for greater than 1 s.
Action Taken When the DTC Sets
DTC P0627, P0628 and P0629 are Type A DTCs.
Conditions for Clearing the DTC
DTC P0627, P0628 and P0629 are Type A DTCs.
Reference Information
Schematic Reference
Engine Controls Schematics
Connector End View Reference
Component Connector End Views
Electrical Information Reference
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
| 1. |
Ignition ON, command the Fuel
Pump Relay ON and OFF with a scan tool. You should hear and feel an
audible click. |
| 2. |
Operate the vehicle within the
Conditions for Running the DTC to verify the DTC does not reset.
You may also operate the vehicle within the conditions that you
observed from the Freeze Frame/Failure Records data. |
Circuit/System Testing
| 1. |
Ignition OFF, disconnect the
KR23A Fuel Pump Relay. |
| 2. |
Test for less than 5 Ω
between the ground circuit terminal 85 and ground. |
| ⇒ |
If greater than the specified range, test the
ground circuit for an open/high resistance. |
| 3. |
Connect a test lamp between
the control circuit terminal 86 and ground. |
| 4. |
Ignition ON, command the Fuel
Pump Relay ON and OFF with a scan tool. The test lamp should turn
ON and OFF when changing between the commanded states. |
| ⇒ |
If the test lamp is always ON, test the control
circuit for a short to voltage. If the circuit tests normal,
replace the K20 Engine Control Module. |
| ⇒ |
If the test lamp is always OFF, test the control
circuit for a short to ground or an open/high resistance. If the
circuit tests normal, replace the K20 Engine Control Module. |
| 5. |
If all circuits test normal,
test or replace the KR23A Fuel Pump Relay. |
Component Testing
Relay Test
| 1. |
Ignition OFF, disconnect the
fuel pump relay. |
| 2. |
Test for 70-110 Ω of
resistance between terminals 85 and 86. |
| ⇒ |
If not within the specified range, replace the
KR23A Fuel Pump Relay. |
| 3. |
Test for infinite resistance
between the following terminals: |
| ⇒ |
If not the specified value, replace the KR23A Fuel
Pump Relay. |
| 4. |
Install a 20 A fused jumper
wire between relay terminal 85 and B+. Install a jumper wire
between relay terminal 86 and ground. Test for less than 2 Ω
of resistance between terminals 30 and 87. |
| ⇒ |
If greater than the specified range, replace the
KR23A Fuel Pump Relay. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
Control Module References for ECM replacement, setup and
programming
|
