DTC P0627-P0629 - LLU
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
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Short to Ground
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Open/High Resistance
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Short to Voltage
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Signal Performance
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Control Circuit
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P0628 00
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P0627 00
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P0629 00
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-
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Ground
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-
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-
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-
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-
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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
• |
The ignition is ON or the engine is running. |
• |
The ignition voltage is between 11-18 V. |
• |
These 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 voltage for greater than 1 s.
Action Taken When the DTC Sets
• |
DTCs P0627 00, P0628 00 and
P0629 00 are Type D DTCs. |
• |
Depending on the condition, the engine may not
start. |
Conditions for Clearing the DTC
DTCs P0627 00, P0628 00 and P0629 00 are
Type D 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
Note: If you were sent here
from engine cranks but does not run proceed to Circuit/System
Testing.
- Ignition ON, command the Fuel Pump Relay ON and OFF
with a scan tool. You should hear and feel an audible click with
the KR23A Fuel Pump Relay.
- Ignition ON, view the DTC information with a scan
tool. DTC P0628 00, P0629 00 should not set.
- 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
- Ignition OFF, remove the KR23A Fuel Pump Relay,
from the underhood fuse block.
- Test for less than 5 Ω between the ground circuit
terminal 86 and ground.
⇒ |
If greater than the specified range, test the
ground circuit for an open/high resistance. |
- Verify that a test lamp does not illuminate between
the control circuit terminal 85 and ground.
⇒ |
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. |
- Install the KR23A Fuel Pump Relay in the
underbonnet fuse block and disconnect the harness connector X1
from the K20 Engine Control Module.
- Install a 20 A fused jumper on the ECM connector
X1 terminals 2. Momentarily touch the end of the fused jumper
to B+, you should hear and feel an audible click from the
KR23A Fuel Pump Relay.
⇒ |
If the relay does not click, 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. |
- If all circuits test normal, test or replace the
KR23A Fuel Pump Relay.
Component Testing
Relay Test
- Ignition OFF, disconnect the KR23A Fuel Pump
Relay.
- Measure for 70-110 Ω between terminals 85
and 86 of the KR23A Fuel Pump Relay.
⇒ |
If the resistance is not within the specified
range, replace the KR23A Fuel Pump Relay. |
- Measure for infinite resistance between following
terminals of the KR23A Fuel Pump Relay:
⇒ |
If continuity is detected, replace the
KR23A Fuel Pump Relay. |
- Connect a 20 A fused jumper wire from the
positive terminal of the battery to KR23A Fuel Pump Relay
terminal 86. Connect a jumper wire from the negative terminal
of the battery to KR23A Fuel Pump Relay terminal 85.
Measure for less than 5 Ω between KR23A Fuel Pump Relay
terminal 30 and KR23A Fuel Pump Relay socket
terminal 87.
⇒ |
If the resistance measures more than 5 Ω,
replace the KR23A Fuel Pump Relay. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
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