1992 Infiniti Q45 BaseFACTORY OEM SERVICE PROCEDURE

Throttle Control Module (TCM)

  1. TCM unit has one LED. Self-diagnostic system is functioning when ignition switch is in ON or START position. The malfunction code is indicated by number of LED flashes.
  2. A long (0.6 second) LED flash indicates number of ten digits. Short flash (0.3 second) indicates number of single digits. Code 12 would be one long flash (0.6 second) and 2 short flashes (0.3 second). See Fig 1 . For trouble code identification, see TCM TROUBLE CODE IDENTIFICATION table.
  3. Most diagnostic results will remain in TCM memory, except for Codes 13, 14 and 33. These 3 codes will be erased after a normal signal is read. Other diagnostic results can be erased by any one of the following methods.
  4. Depress accelerator fully and set neutral switch to OFF (automatic transmission in other than "P" or "N" positions). Turn ignition switch to ON position. Set neutral switch to ON position and release accelerator. This will erase all codes.
  5. If, during diagnosis, an item or component is found to be okay, and no repair is attempted during 50 ignition switch ON period, codes on that item or component will be erased.
  6. If back-up power supply is disconnected for more than one minute, diagnostic codes on all items are erased. In addition, any values learned by system are also erased.
TCM TROUBLE CODE IDENTIFICATION

Code No. Malfunction
11 Throttle Sensor Circuit
12 Secondary Throttle Sensor Circuit
13 Secondary Throttle Valve Operating Signal Circuit
14 Engine Temperature Sensor For TCM Circuit
21 Throttle Motor Circuit (Operation & Open Circuit Check)
22 Throttle Motor Circuit (Short Circuit Check)
23 Throttle Motor Relay Circuit (Short)
24 Throttle Motor Relay Circuit (Open)
32 Secondary Throttle Valve Return Spring Broken
33 Neutral Switch Circuit
34 Power Supply Circuit (For Sensor)
55 No Malfunction In Above Circuits
Fig 1: Example of TCM Flash Code (Codes 12 & 33 Shown)
G92J00892Courtesy of NISSAN MOTOR CO., U.S.A.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.