The engine control module (ECM) provides a ground to the coil side of the fuel pump relay. When the ignition switch is first turned On, the ECM energizes the fuel pump relay, which applies power to the fuel pump. The ECM enables the fuel pump relay as long as the engine is cranking or running, and crankshaft reference pulses are received. If no crankshaft reference pulses are received, the ECM de-energizes the fuel pump relay after 3 seconds. If the ECM detects low voltage on the fuel pump relay control circuit, this DTC sets.
This diagnostic procedure supports the following DTC:
DTC P1230 Fuel Pump Relay Control Circuit Low Voltage
• | The ignition is ON or the engine is running. |
• | The ignition voltage is more than 10 volts. |
• | DTC P1230 runs continuously once the above conditions are met. |
• | The ECM detects that the commanded state of the driver and the actual state of the driver do not match. |
• | The above conditions are present for more than 5 seconds. |
• | The malfunction indicator lamp (MIL) will illuminate. |
• | The ECM will record operating conditions at the time the diagnostic fails. This information will be stored in the Freeze Frame and Failure Records buffers. |
• | The coolant fan turns ON. |
• | The MIL will turn OFF after consecutive ignition cycles in which the diagnostic runs without a fault. |
• | DTCs can be cleared by using the scan tool. |
• | Disconnect the ECM battery feed for 10 seconds. |
The following conditions may have caused the fuel pump fuse to open:
• | The fuse is faulty. |
• | There is an intermittent short to ground in the ignition 1 voltage circuit of the fuel pump relay. |
Listen for a click when the fuel pump relay operates. When the fuel pump relay is commanded On with the scan tool, the ECM pulses the fuel pump relay ON and OFF several times.
For an intermittent condition, refer to Intermittent Conditions .
Fuel Pump Relay Terminal Identification | |
---|---|
B+ | FP Control |
Ignition 1 Voltage | FP Motor |
Front of Vehicle |
The numbers below refer to the step numbers on the diagnostic table.
This step verifies that the ECM is providing a ground to the fuel pump relay.
This step tests the Ignition 1 Voltage circuit of the fuel pump relay.
Step | Action | Yes | No | ||||||
---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics Connector End View Reference: Engine Control Module Connector End Views or Engine Controls Connector End Views | |||||||||
1 | Did you perform the Diagnostic System Check - Engine Controls? | Go to Step 2 | |||||||
Does the fuel pump relay turn ON and OFF? | Go to Step 3 | Go to Step 4 | |||||||
3 |
Did the DTC fail this ignition? | Go to Step 4 | Go to Diagnostic Aids | ||||||
Does the test lamp pulse ON and OFF? | Go to Step 5 | Go to Step 6 | |||||||
Does the test lamp pulse ON and OFF? | Go to Step 7 | Go to Step 9 | |||||||
6 | Test the control circuit of the fuel pump relay for one of the following conditions:
Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 8 | ||||||
7 | Test for an intermittent and for a poor connection at the fuel pump relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 10 | ||||||
8 | Test for an intermittent and for a poor connection at the engine control module (ECM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 11 | ||||||
9 |
Did you complete the repair? | Go to Step 12 | -- | ||||||
10 | Replace the fuel pump relay. Did you complete the replacement? | Go to Step 12 | -- | ||||||
11 | Replace the ECM. Refer to Engine Control Module Replacement . Did you complete the replacement? | Go to Step 12 | -- | ||||||
12 |
Did the DTC fail this ignition? | Go to Step 2 | Go to Step 13 | ||||||
13 | Are there any DTCs that have not been diagnosed? | System OK |