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No voltage to PCM after troubleshooting radiator fan problem. Dealer says replace PCM.

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2009 chevy hhr speakers don't work and a/c radiator fan won't come on


What engine does it have ?

Cooling Fan Control 2.0L
The engine cooling fan is a variable speed fan. The engine control module (ECM) controls the fan speed by sending a pulse width modulated (PWM) signal to the cooling fan control module. The cooling fan control module varies the voltage drop across the engine cooling fan motor in relation to the PWM signal. The cooling fan speed can be adjusted from 10 percent to 94 percent duty cycle. 94 percent is considered high speed fan.
Cooling Fan Control 2.2L or 2.4L
The engine cooling fan system consists of one cooling fan and one relay. Voltage is supplied to the relay through a fuse. The engine control module (ECM) controls the fan operation by grounding the cool fan relay control circuit. When the cool fan relay is energized, voltage is delivered to the cooling fan motor. The cooling fan motor is grounded through its own ground circuit.
When the request for fan activation is withdrawn, the fan may not turn OFF until the ignition switch is moved to the OFF position or the vehicle speed exceeds approximately 10 mph. This is to prevent the fan from cycling ON and OFF excessively at idle.


Just one speaker doesn't work ? Do you know how to do automotive electrical testing ? That's how to find both your problems . Speakes work by electrical inpluse's . The A/C radiator ( condenser ) fan also works by B+ voltage through a fuse an a relay , controlled by the engine electronic control module or PCM - powertrain control module . When you push the A/C turn on button , it sends a signal to the PCM . The PCM will then energize the radiator fan relay turning on the fan . Check fuse in the under hood fuse box , If the fuse is blown you have a electrical short , too much current flow . Plus if the PCM sees too much pressure in the A/C system it will not let the A/C work .

Mar 31, 2017 | Cars & Trucks

2 Answers

1996 Saturn sl2 radiator fan problem does not turn on changed fuse and relay and motor


Pull the plug off the temperature sensor. This throws the PCM in default mode. The fans should come on at high mode. If not look to wiring, fuses, relays and the PCM. Scanner helps a lot.

Aug 07, 2016 | Saturn Cars & Trucks

1 Answer

Radiator Fan Not Working Properly


If you see pin 87 you must see 30 ! 30 should have B+ voltage as will 86 . Pin 85 is to the engine computer ,PCM/ECM . If you jump to pin 85 you run the risk of frying the PCM on that circuit . A transistor inside the PCM is switched on when the engine temp gets to hot . The PCM supply's a ground for the control side of the relay energizing the relay an closing the contacts inside the relay sending B+ voltage from pin 87 to pin 30 to the fans ! Go to you tube an check out video on relay's an how they work .

Feb 04, 2016 | Cars & Trucks

2 Answers

2004 Venture Chevrolet minivan cooling fan circut


Are you talking about the radiator fan? How hot does the engine get in degrees F? Some makes and models, the radiator fan won't turn on till about 220 degrees F. Check for applicable trouble codes, see if any code that refers to the radiator fan circuit or coolant temp sensor? Some of the national brand auto stores will check codes for free.

Of course, as far as overheating in general, you have the thermostat--water pump and other possible issues. Are you losing coolant?

Dec 14, 2014 | Chevrolet Cars & Trucks

1 Answer

Code P2247


DTC P2247: Front A/F Sensor (Bank 2, Sensor 1) VCENT Line High Voltage

NOTE:
Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information.
Information marked with an asterisk (*) applies to the front bank (Bank 2).
Turn the ignition switch ON (II).
Clear the DTC with the HDS.
Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) until the radiator fan comes on, then let it idle for 2 minutes .
Check for Temporary DTCs or DTCs with the HDS.
Is DTC P2243 and/or P2247* indicated?

YES - Go to step 5.

NO - Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the A/F sensor (Sensor 1) and the ECM/PCM.

Turn the ignition switch OFF.
Jump the SCS line with the HDS.
Disconnect the A/F sensor (Sensor 1) 8P connector.
Disconnect ECM/PCM connector B (24P).




Connect A/F sensor (Sensor 1) 8P connector terminal No. 8 to body ground with a jumper wire.




Check for continuity between ECM/PCM connector terminal B13 (B21)* and body ground.
Is there continuity?

YES - Go to step 11.

NO - Repair open in the wire between the ECM/PCM (B13 (B21)*) and the A/F sensor (Sensor 1), then go to step 15.

Remove the jumper wire from the A/F sensor (Sensor 1) 8P connector, then reconnect ECM/PCM connector B (24P).
Start the engine. Hold the engine speed at 3,000 rpm without load (in Park or neutral) until the radiator fan comes on, then let it idle for 2 minutes .




Measure voltage between ECM/PCM connector terminals B13 (B21)* and D10.
Is there about 0.2 V or less?

YES - Go to step 21.

NO - Go to step 14.

Replace the A/F sensor (Sensor 1).
Reconnect all connectors.
Turn the ignition switch ON (II).
Reset the ECM/PCM with the HDS.
Do the ECM/PCM idle learn procedure. See: Programming and Relearning
Check for Temporary DTCs or DTCs with the HDS.
Are any Temporary DTCs or DTCs indicated?

YES - If DTC P2243 and/or P2247* is indicated, check for poor connections or loose terminals at the A/F sensor (Sensor 1) and the ECM/PCM, then go to Step 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.

NO - Go to step 20.

Monitor the OBD STATUS for DTC P2243 and/or P2247* in the DTCs MENU with the HDS.
Does the screen indicate PASSED?

YES - Troubleshooting is complete.

NO - If the screen indicates FAILED, check for poor connections or loose terminals at the A/F sensor (Sensor 1) and the ECM/PCM, then go to step 1. If the screen indicates NOT COMPLETED, go to step 18 and recheck.

Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM.
Check for Temporary DTCs or DTCs with the HDS.
Are any Temporary DTCs or DTCs indicated?

YES - If DTC P2243 and/or P2247* is indicated, check for poor connections or loose terminals at the A/F sensor (Sensor 1) and the ECM/PCM, then go to step 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.

NO - If the ECM/PCM was updated, troubleshooting is complete. If the ECM/PCM was substituted, replace the original ECM/PCM.

Jun 23, 2013 | 2006 Honda Odyssey

1 Answer

What's your problem?AutoZone computer read no ASD relay voltage at PCM ? 2001 jeep cherokee sport --electric radiator fan won't come on?


Sounds like maybe the relay is not working. Posible causes might be a bad relay, no power to the ralay, a grounded wire from relay to the PCM (computer) ect...

May 28, 2012 | Cars & Trucks

1 Answer

1999 Jeep Cherokee Sport wont shift into overdrive P1491


P1491 - Radiator Fan Control Relay Circuit Open Or Shorted

When monitored: with the ignition key on, battery voltage greater than 10.0 volts and
the pcm requests the radiator fan to be turned on.
Set condition: an open or shorted circuit is detected in the radiator fan relay control
circuit.

Possible causes
radiator fan ctrl rly circuit wire harn intermittent defect
radiator fan ctrl rly circuit wire harn observable defect
radiator fan relay ground circuit open
rad fan relay control circuit open
radiator fan relay control circuit short to ground
rad fan control relay defective
pcm defective

Check ot and keep us updared.

Oct 15, 2011 | 1999 Jeep Cherokee

2 Answers

P1491 diagnostics code for 2003 Jeep Grand Cherokee



Trouble Code: P1491 You PCM does not sense current to radiator fan when it turns it on. Is the fan coming on or not? Usually not when you have this code. Problem can be with the fuse, relay, wiring or fan itself. First check the fuse. If good, next try swapping the relay with another one in the engine compartment relay box, such as the horn relay.
Let the car warm up and see if the fan will come on. If yes, get a new relay. If not, either use a test light to see if there is voltage at the fan connector when the engine is on and hot, or else test the fan motor by hotwiring it to the battery. If none of this works, please get back to me for how to troubleshoot the wiring.


Radiator Fan Control Relay Circuit Malfunction
Possible Causes:


Radiator fan control relay circuit is open or shorted to ground Radiator fan control relay circuit is open (test power to IGN) Radiator fan control relay is damaged or has failed PCM has failed

Nov 10, 2010 | 2003 Jeep Grand Cherokee

3 Answers

My fan wont work.when the engine is hot.


First check the fuse in the engine compartment relay box. If not the fuse, you will need a 12 volt test light (or voltmeter) to troubleshoot, as there are several possible reasons. With the engine hot and running, pull the connector off the fan and use your test light to see if there is voltage in the connector. If there is voltage, replace the motor. In no voltage, move on to the relay. pull the relay out of the socket (in the same box as the fuse). If it clicks when you pull it out, your wiring to the fan is bad. If it doesn't click, try switching it with a similar relay. If a different relay clicks when put in the fan relay socket, your fan should now be coming on. If neither relay clicks, interrogate the relay socket with your test light. Put your clip on a chassis ground point and probe the terminals into the relay socket. If 2 of the sockets light up the light, the system is trying to throw the relay. If not, the likely problem is the PCM or the coolant temp sensor, which is read by the PCM. Hopefully you don't get to this point, as I assume your temp gage is working. Let me know if you have questions.

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Oct 27, 2010 | 2003 Pontiac Sunfire

1 Answer

Overheating engin when at idel, fan not working


does both the hoses get hot bottom and top? this will tell you if theres flow through the radiator. If you have a voltage tester test the wires on the fan connecter check there is current going to the fan if so replace the fan its a common problem as previously stated. 
if there is no power to the fan when the vehicle should be turning it on i.e. its hot enough check the fan relay under the hood.

Nov 23, 2008 | 1999 Jeep Grand Cherokee

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