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Home >> Mazda >> 2011 >> 3 Mazdaspeed, 2.3 3 >> Repair and Diagnosis >> Body & Frame >> Door Locks >> On-Board Diagnostic [Advanced Keyless Entry And Push Button Start System] >> DTC P1794:16 [Advanced Keyless Entry And Push Button Start System]
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DTC P1794:16 [Advanced Keyless Entry And Push Button Start System]

DESCRIPTION  Low voltage in power supply circuit (+B2) 
DETECTION CONDITION 
  • Keyless control module power supply circuit (+B2) voltage is less than 8.5 V  for 5 s. 
POSSIBLE CAUSE 
  • Charging system malfunction
    • PCM DTC is stored
  • Battery malfunction
  • Generator malfunction
  • Keyless control module connector or terminals malfunction
  • Open circuit or short to ground in keyless control module power supply circuit
    • Short to ground in wiring harness between battery positive terminal and keyless control module terminal 1F
    • ENG+B 10 A fuse malfunction
    • Open circuit in wiring harness between battery positive terminal and keyless control module terminal 1F
  • Keyless control module malfunction
G07874868
DIAGNOSTIC PROCEDURE

Step Inspection Action
1 CONFIRM PCM DTC 
Yes Go to the applicable DTC inspection.
(See DTC TABLE [LF, L5] ).
(See DTC TABLE [L3 WITH TC] ).
No Go to the next step.
2 INSPECT BATTERY 
Yes Recharge or replace the battery, then go to Step 6.
(See BATTERY RECHARGING [LF, L5] ).
(See BATTERY RECHARGING [L3 WITH TC] ).
(See BATTERY REMOVAL/INSTALLATION [LF, L5] ).
(See BATTERY REMOVAL/INSTALLATION [L3 WITH TC] ).
No Go to the next step.
3 INSPECT GENERATOR 
Yes Replace the generator, then go to Step 6.
(See GENERATOR REMOVAL/INSTALLATION [LF, L5] ).
(See GENERATOR REMOVAL/INSTALLATION [L3 WITH TC] ).
No Go to the next step.
4 INSPECT KEYLESS CONTROL MODULE CONNECTOR AND TERMINALS 
  • Switch the ignition to off.
  • Disconnect the negative battery cable.
  • Disconnect the keyless control module connector.
  • Inspect the connector and terminals (corrosion, damage, pin disconnection).
  • Is there any malfunction?
Yes Repair or replace the connector or terminals, then go to Step 6.
No Go to the next step.
5 INSPECT POWER SUPPLY CIRCUIT (+B2) FOR OPEN CIRCUIT OR SHORT TO GROUND 
  • Keyless control module connector is disconnected.
  • Reconnect the negative battery cable.
  • Measure the voltage at the following terminal (wiring harness-side):
    • Keyless control module terminal 1F
  • Is the voltage B+? 
Yes Go to the next step.
No Inspect the ENG+B 10 A fuse.
  • If the fuse is melt:
    • Repair or replace the wiring harness for a possible short to ground.
    • Replace the fuse.
  • If the fuse is deterioration:
    • Replace the fuse.
  • If the fuse is normal:
    • Repair or replace the wiring harness for a possible open circuit.

Go to the next step.
6 VERIFY TROUBLESHOOTING COMPLETED 
Yes Replace the keyless control module, then go to the next step.
(See KEYLESS CONTROL MODULE REMOVAL/INSTALLATION ).
No Go to the next step.
7 VERIFY THAT NO OTHER DTCs ARE PRESENT 
  • Are any DTCs present?
Yes Go to the applicable DTC inspection.
(See DTC TABLE [ADVANCED KEYLESS ENTRY AND PUSH BUTTON START SYSTEM] ).
No DTC troubleshooting completed.