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1999 Saturn SL2 P0410 Fault: Secondary Air Pump Not Grounded or Cycling Correctly

Model: 1999 Saturn SL2 Fault Code: P0410 Posted: 2010-03-16 21:01

I'm experiencing a P0410 diagnostic trouble code with the SES light illuminated on my 1999 Saturn SL2. The air pump fuse (30 amp) has been tested and is functioning properly. I've also verified that the control relay is operational. After disconnecting the air pump connector, I applied 12VDC directly to the pump terminals and it operated normally. When I removed the relay and connected a jumper across its contact points, the pump activated — confirming the motor itself is functional. However, when the engine is running, I observe +12VDC on one side of the coil but no negative voltage (ground) on the other side. This suggests a grounding issue in the circuit. My questions are: - Is it normal for the secondary air pump to run continuously when the engine is ON? - Does the system cycle the pump on and off based on demand (e.g., coolant temperature)? - Should the negative terminal of the coil always have a ground connection, or is this only active during specific operating conditions? - Is my temporary fix — jumpering a ground to the relay coil — safe or effective in the long term? Any insights into how the PCM controls the air pump would be greatly appreciated. Thanks for your help.

Related fault codes
P0410
Comments (3)
Anonymous 2010-03-20 10:29

The secondary air pump typically runs during engine startup, with runtime varying between 0 and 65 seconds depending on coolant temperature — colder temperatures result in longer operation. Power to the pump is supplied via the air pump relay, which receives its ground signal from the Powertrain Control Module (PCM). The issue may be whether the pump fails to activate or remains active after startup. When you mention 'coil,' are you referring to the air pump control relay? If so, could you clarify if you're testing the feed side or the control side of the relay?

Anonymous 2010-03-20 19:23

Rash thanks for the info on the control system I was measuring the voltage to both sides of the coil and the engine was warm hence no negative voltage from the PCM. I have since pulled the battery cable off and reset the code. it has stayed off so far. I'm guessing / hoping that my troubleshooting has either freed the motor, or cleaned a connection or reset the pcm (again). I'll update here if it comes on again. For now I hope it stays off. Again thanks for letting me know how this is turned on.

Anonymous 2010-03-20 19:24

Thanks for clarifying the control system! I measured voltage on both sides of the coil and found no negative voltage because the engine was warm — this explains why the PCM wasn't providing a ground signal. After removing the battery cable and performing a full reset, the P0410 code has not reappeared. I suspect that my troubleshooting efforts either cleared a stuck motor connection or improved a loose wire, or possibly reset the PCM. I’ll monitor the system closely in the coming days — if the code returns, I’ll update here. For now, I’m hopeful it remains resolved. Thanks again for explaining how the pump is activated!