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DTC 51: Injector

Search For Malfunctioning Circuit

Using a listening device, search for circuit which does not produce injector operating sound at idle. See Fig 1 .

Search For Malfunctioning Circuit Using CONSULT

Perform POWER BALANCE in ACTIVE TEST mode. Search for circuit which does not produce a momentary engine speed drop.

Fig 1: DTC 51, Checking For Injector Operating Sound (Q45)
Courtesy of NISSAN MOTOR CO., U.S.A.

NOTE: When either cylinders No. 1, 3, 5 and 7 or cylinders No. 2, 4, 6 and 8 are all not operating, go to next step. If there is a different malfunction, go to step 4).

Check Power Supply I

Turn ignition off. Disconnect EFI sub-harness No. 1, 4-pin connector. Measure voltage between EFI sub-harness No. 1 connector terminals "b" (Red wire) and ground, and "d" (Red wire) and ground. See Fig 2 and Fig 3 . If battery voltage is present, go to next step. If battery voltage is not present, verify harness continuity between EFI sub-harness No. 1 connector and Blue EFI harness connector. If continuity is present, go to next step. If continuity is not present, repair harness or connectors as necessary.

Fig 2: Locating EFI Sub-Harness No. 1 Connector (Q45)
Courtesy of NISSAN MOTOR CO., U.S.A.

Fig 3: DTC 51, Checking Power Supply I (Q45)
Courtesy of NISSAN MOTOR CO., U.S.A.

Check Power Supply II

Turn ignition off and disconnect EFI sub-harness No. 1, 4-pin and 8-pin connectors. See Fig 2 . Verify harness continuity between 4-pin and 8-pin connector (injector side) terminals as follows:
- Terminal "e" (Red wire) and terminal "i" (Blue wire).
- Terminal "e" (Red wire) and terminal "j" (Blue/Black wire).
- Terminal "e" (Red wire) and terminal "n" (Red/Black wire).
- Terminal "e" (Red wire) and terminal "o" (Red/Yellow wire).
- Terminal "g" (Red wire) and terminal "k" (Blue/Yellow wire).
- Terminal "g" (Red wire) and terminal "l" (Blue/Red wire).
- Terminal "g" (Red wire) and terminal "m" (Red wire).
- Terminal "g" (Red wire) and terminal "p" (Red/Green wire).
See Fig 4 . If continuity is present, go to step 6). If continuity is not present, disconnect each injector harness connector. Verify continuity between following terminals:
- Terminals "e" and "r".
- Terminals "g" and "r".
- Terminals "i" and "q".
- Terminals "j" and "q".
- Terminals "k" and "q".
- Terminals "l" and "q".
- Terminals "m" and "q".
- Terminals "n" and "q".
- Terminals "o" and "q".
- Terminals "p" and "q".
See Fig 5 and Fig 6 . If continuity is present, go to next step. If continuity is not present, repair harness or connectors as necessary.

Check Component

Inspect each injector. See I - SYSTEM/COMPONENT TESTS article. Replace if necessary and perform FINAL CHECK .

Check Output Signal Circuit

Disconnect ECM harness connector. Verify harness continuity between following ECM connector terminals and EFI 8-pin connector terminals:
- EFI terminal "s" and ECM terminal No. 113 (Blue/Green wire).
- EFI terminal "t" and ECM terminal No. 105 (Blue/Yellow wire).
- EFI terminal "u" and ECM terminal No. 103 (Blue/Black wire).
- EFI terminal "v" and ECM terminal No. 101 (Blue wire).
- EFI terminal "w" and ECM terminal No. 106 (Red/Green wire).
- EFI terminal "x" and ECM terminal No. 114 (Red/Yellow wire).
- EFI terminal "y" and ECM terminal No. 112 (Red/Black wire).
- EFI terminal "z" and ECM terminal No. 110 (Red wire).
See Fig 7 . If continuity is not present, repair harness or connectors as necessary. If continuity is present, inspect ECM pin terminals for damage or check for bad connection of ECM harness connector. Perform FINAL CHECK .

Fig 4: DTC 51, Checking Power Supply II (Q45)
Courtesy of NISSAN MOTOR CO., U.S.A.

Fig 5: Locating Injector Harness Connectors (Q45)
Courtesy of NISSAN MOTOR CO., U.S.A.

Fig 6: DTC 51, Checking Injector Harness Continuity (Q45)
Courtesy of NISSAN MOTOR CO., U.S.A.

Fig 7: DTC 51, Checking Output Signal Circuit (Q45)
Courtesy of NISSAN MOTOR CO., U.S.A.