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92 vette no power to fuel pump fuse

mvsvette

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Mar 7, 2016
Messages
19
Location
Menifee Ca.
Corvette
92 Corvette
I have a 92 vette. I recently was receiving codes 26 and 32 indicating something wrong with the air pump. I disconnected the plug to the relay and put in a jumper wire to see if the pump would come on. No luck. I took it apart and it was full of water and the motor was heavily corroded. I know I need a new one. Now the real problem, since then, the fuel pump will not come on for the 2 seconds and I have no power to the fuse and the fuse is good. When the key is turned on engine off, no SERVICE ENGINE SOON light is displayed. Also, I jumped the A and B on the ALDL connector and the fans don't run. I have power to the ECM fuse. Going nuts please help. Thanks in advance.
 

ecss

Well-known member
Joined
Nov 27, 2004
Messages
649
Location
Windsor Mill, MD
Corvette
89 Brilliant Red Metallic
I have a 92 vette. I recently was receiving codes 26 and 32 indicating something wrong with the air pump. I disconnected the plug to the relay and put in a jumper wire to see if the pump would come on. No luck. I took it apart and it was full of water and the motor was heavily corroded. I know I need a new one. Now the real problem, since then, the fuel pump will not come on for the 2 seconds and I have no power to the fuse and the fuse is good. When the key is turned on engine off, no SERVICE ENGINE SOON light is displayed. Also, I jumped the A and B on the ALDL connector and the fans don't run. I have power to the ECM fuse. Going nuts please help. Thanks in advance.

Disconnect the ECM Green connector.
Verify you have 12 volts (Hot all the time) on the Orange wire at pin 6 and pin 17.

12 volts for the SES light comes from the Cluster 5 amp fuse which is hot when the ignition switch is On.
The ECM grounds one side of the bulb to turn on the SES indicator.

Only thing left to check is the grounds for the ECM.
Disconnect the Red ECM connector.
Pin 6, 17 and 22 Tan/White wires should have zero resistance to the negative battery terminal.

If everything checks out it points to the ECM being bad.
 

mvsvette

Member
Joined
Mar 7, 2016
Messages
19
Location
Menifee Ca.
Corvette
92 Corvette
Disconnect the ECM Green connector.
Verify you have 12 volts (Hot all the time) on the Orange wire at pin 6 and pin 17.

12 volts for the SES light comes from the Cluster 5 amp fuse which is hot when the ignition switch is On.
The ECM grounds one side of the bulb to turn on the SES indicator.

Only thing left to check is the grounds for the ECM.
Disconnect the Red ECM connector.
Pin 6, 17 and 22 Tan/White wires should have zero resistance to the negative battery terminal.

If everything checks out it points to the ECM being bad.

Thank you ECSS for the reply. Did the checks you suggested
and found the following, checked pins 6 and 17 green connector both have 12 volts. Checked pins 6, 17, 22 red connector, all show .03 on my multi meter. Not sure if I'm testing for ground correctly.
 

ecss

Well-known member
Joined
Nov 27, 2004
Messages
649
Location
Windsor Mill, MD
Corvette
89 Brilliant Red Metallic
Thank you ECSS for the reply. Did the checks you suggested
and found the following, checked pins 6 and 17 green connector both have 12 volts. Checked pins 6, 17, 22 red connector, all show .03 on my multi meter. Not sure if I'm testing for ground correctly.

When you check the red connector pins 6, 17 and 22 set the meter to read ohms. Should have close to zero ohms of resistance from the pin to the negative battery terminal.

If you have power and ground to the ECM it should light the SES indicator when the ignition switch is On.
It should also ground the fuel pump relay for about 2 seconds to prime the engine. You also verified you have 12 volts on the ECM fuse when the ignition is On. You connected Pin A to Pin B on the diagnostic connector turned the ignition On, the SES indicator did not blink 12 and any error codes and the fans did not come on. That confirms the ECM has a problem.

If you connect Pin A to Pin G on the diagnostic connector and turn the ignition On look at the Speedometer LCD and you should see the modules displayed. The CCM will poll the ECM which is module 4. If you get an Err for module 4 that indicates the CCM can't communicate with the ECM. The CCM is module 1. Module 9 is the ABS/ASR module

The diag. connector looks like this.

F E D C B A
G H J K L M
 
Last edited:

mvsvette

Member
Joined
Mar 7, 2016
Messages
19
Location
Menifee Ca.
Corvette
92 Corvette
When you check the red connector pins 6, 17 and 22 set the meter to read ohms. Should have close to zero ohms of resistance from the pin to the negative battery terminal.

If you have power and ground to the ECM it should light the SES indicator when the ignition switch is On.
It should also ground the fuel pump relay for about 2 seconds to prime the engine. You also verified you have 12 volts on the ECM fuse when the ignition is On. You connected Pin A to Pin B on the diagnostic connector turned the ignition On, the SES indicator did not blink 12 and any error codes and the fans did not come on. That confirms the ECM has a problem.

If you connect Pin A to Pin G on the diagnostic connector and turn the ignition On look at the Speedometer LCD and you should see the modules displayed. The CCM will poll the ECM which is module 4. If you get an Err for module 4 that indicates the CCM can't communicate with the ECM. The CCM is module 1. Module 9 is the ABS/ASR module

The diag. connector looks like this.

F E D C B A
G H J K L M

I did have it on ohms and all the test you recommended came out good. No SES light with key on. No fuel pump 2 sec prime. I could hear it run when sitting in the car, now nothing. Correct me if I'm wrong, if you apply12 volts to the G connector, shouldn't the fuel pump run ?
No fans when probing A and B.
 

ecss

Well-known member
Joined
Nov 27, 2004
Messages
649
Location
Windsor Mill, MD
Corvette
89 Brilliant Red Metallic
I did have it on ohms and all the test you recommended came out good. No SES light with key on. No fuel pump 2 sec prime. I could hear it run when sitting in the car, now nothing. Correct me if I'm wrong, if you apply12 volts to the G connector, shouldn't the fuel pump run ?
No fans when probing A and B.

On a 92 with the LT1 when you connect Pin A (ground) to Pin G on the diagnostic connector you place the CCM in a diagnostic mode. It polls the modules and displays the information in the Speedometer LCD area when you turn the ignition On. You do not apply 12 volts to pin G to get the fuel pump to run. Since you have no SES indicator on and the Fans don't come on when you connect Pin A to Pin B something is wrong with the ECM. That's why I recommend you connect Pin G to Pin A. Turn the ignition On and see what displays on the Speedometer LCD area.
 

mvsvette

Member
Joined
Mar 7, 2016
Messages
19
Location
Menifee Ca.
Corvette
92 Corvette
On a 92 with the LT1 when you connect Pin A (ground) to Pin G on the diagnostic connector you place the CCM in a diagnostic mode. It polls the modules and displays the information in the Speedometer LCD area when you turn the ignition On. You do not apply 12 volts to pin G to get the fuel pump to run. Since you have no SES indicator on and the Fans don't come on when you connect Pin A to Pin B something is wrong with the ECM. That's why I recommend you connect Pin G to Pin A. Turn the ignition On and see what displays on the Speedometer LCD area.

I will do that and let you know the outcome. I'll have to check it tomorrow. I appreciate all you help and knowledge. Gotta get my baby fixed.
 

mvsvette

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Joined
Mar 7, 2016
Messages
19
Location
Menifee Ca.
Corvette
92 Corvette
I will do that and let you know the outcome. I'll have to check it tomorrow. I appreciate all you help and knowledge. Gotta get my baby fixed.


UPDATE: Ran jumper from A to G. Module 1, C41. Module 4 ERR, Module 9 ERR. Looks like I need an ECM.
 

ecss

Well-known member
Joined
Nov 27, 2004
Messages
649
Location
Windsor Mill, MD
Corvette
89 Brilliant Red Metallic
UPDATE: Ran jumper from A to G. Module 1, C41. Module 4 ERR, Module 9 ERR. Looks like I need an ECM.

The modules communicate via a serial bus. Module 1 code 41 indicates a serial line communication problem.
Since you have ERR for Module 4 the ECM and also Module 9 the ABS/ASR you need to verify the serial bus is working.

If you have the C68 Auto Climate Control system try this. Turn the ignition On and press the Eng/Metric switch on the Driver Info center and see if the temperature displayed in the Heater/AC Control Head switches from Fahrenheit to Celsius.

If that works the serial bus is working and the ECM is probably bad. The ERR for Module 9 also indicates something is wrong the EBCM module which is located in the storage bin behind the drivers seat.

When you turn the ignition On do any ABS or ASR indicator lights come on?

Open the driver side rear storage bin and verify it's not full of water. If no water verify the fuses for the EBCM are not blown.

The EBCM uses the Air Bag 10 amp fuse, the gauges fuse, fusible link J, fusible link K and the Cruise fuse.
The fusible links are located and mounted to a stud behind and below the Battery.
 
Last edited:

mvsvette

Member
Joined
Mar 7, 2016
Messages
19
Location
Menifee Ca.
Corvette
92 Corvette
The modules communicate via a serial bus. Module 1 code 41 indicates a serial line communication problem.
Since you have ERR for Module 4 the ECM and also Module 9 the ABS/ASR you need to verify the serial bus is working.

If you have the C68 Auto Climate Control system try this. Turn the ignition On and press the Eng/Metric switch on the Driver Info center and see if the temperature displayed in the Heater/AC Control Head switches from Fahrenheit to Celsius.

If that works the serial bus is working and the ECM is probably bad. The ERR for Module 9 also indicates something is wrong the EBCM module which is located in the storage bin behind the drivers seat.

When you turn the ignition On do any ABS or ASR indicator lights come on?

Open the driver side rear storage bin and verify it's not full of water. If no water verify the fuses for the EBCM are not blown.

The EBCM uses the Air Bag 10 amp fuse, the gauges fuse, fusible link J, fusible link K and the Cruise fuse.
The fusible links are located and mounted to a stud behind and below the Battery.

Thanks again ECSS. I have checked the fusible links and they all look good visually. When they're bad, do they burn through the heat shrink and wire? I will be checking the other things you mentioned today and will give you an update this evening.
 

ecss

Well-known member
Joined
Nov 27, 2004
Messages
649
Location
Windsor Mill, MD
Corvette
89 Brilliant Red Metallic
Thanks again ECSS. I have checked the fusible links and they all look good visually. When they're bad, do they burn through the heat shrink and wire? I will be checking the other things you mentioned today and will give you an update this evening.

Yes the insulation where the fusible link wire is, will look melted or discolored. You can use a sharp pin or probe to pierce the insulation and verify with a volt meter if the fusible link is open or measure the voltage right at the EBCM which is not easy to do because of its location.

Did the car you're working on develop these problems after you shorted the air pump relay or was this the way you bought the car?
 

mvsvette

Member
Joined
Mar 7, 2016
Messages
19
Location
Menifee Ca.
Corvette
92 Corvette
Yes the insulation where the fusible link wire is, will look melted or discolored. You can use a sharp pin or probe to pierce the insulation and verify with a volt meter if the fusible link is open or measure the voltage right at the EBCM which is not easy to do because of its location.

Did the car you're working on develop these problems after you shorted the air pump relay or was this the way you bought the car?

Climate Control display did not change, it stayed on Fahrenheit. The storage bin is clean and no water in it. Yes, it did develop this problem after I shorted the air pump relay. I don't see any fusible links burnt through or discolored.
 

ecss

Well-known member
Joined
Nov 27, 2004
Messages
649
Location
Windsor Mill, MD
Corvette
89 Brilliant Red Metallic
Climate Control display did not change, it stayed on Fahrenheit. The storage bin is clean and no water in it. Yes, it did develop this problem after I shorted the air pump relay. I don't see any fusible links burnt through or discolored.

When you did the the ENG/MET button test did you remove the A to G jumper wire?
If not try it again with no jumper wire.

Even though the HVAC control head display didn't change to Metric did the Dash Cluster change to Metric which would indicate the button itself is working.

Try disconnecting the negative battery terminal for a few seconds then reconnect. Turn the ignition On. The HVAC will go through a re calibration of the blend door which takes about 30 seconds. When it's done the blower motor will turn on which is normal. Press the blower motor off button.

Turn the ignition Off.
Short A to G and turn the ignition On.
Verify if you still get ERR for the Module 4 ECM and Module 9 ABS/ASR.

If you still get ERR for both modules.
Unplug the four connectors on the back of the ECM to remove it from the circuit.
Run the A to G test again and see if the Module 9 starts working and no ERR is displayed. If it does work that would indicate the ECM is holding down the serial bus and is bad.
 
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mvsvette

Member
Joined
Mar 7, 2016
Messages
19
Location
Menifee Ca.
Corvette
92 Corvette
When you did the the ENG/MET button test did you remove the A to G jumper wire?
If not try it again with no jumper wire.

Even though the HVAC control head display didn't change to Metric did the Dash Cluster change to Metric which would indicate the button itself is working.

Try disconnecting the negative battery terminal for a few seconds then reconnect. Turn the ignition On. The HVAC will go through a re calibration of the blend door which takes about 30 seconds. When it's done the blower motor will turn on which is normal. Press the blower motor off button.

Turn the ignition Off.
Short A to G and turn the ignition On.
Verify if you still get ERR for the Module 4 ECM and Module 9 ABS/ASR.

If you still get ERR for both modules.
Unplug the four connectors on the back of the ECM to remove it from the circuit.
Run the A to G test again and see if the Module 9 starts working and no ERR is displayed. If it does work that would indicate the ECM is holding down the serial bus and is bad.

Yes, I didn't have A and G jumper in. I do have a SYS blinking in the dash. The service ABS light is on as well. Still no change on the dash or climate control when the ENG/MET button is pushed. I now have C13 and C41 in module 1 and ERR on both 4 and 9 even with the ECM disconnected.
 

ecss

Well-known member
Joined
Nov 27, 2004
Messages
649
Location
Windsor Mill, MD
Corvette
89 Brilliant Red Metallic
Yes, I didn't have A and G jumper in. I do have a SYS blinking in the dash. The service ABS light is on as well. Still no change on the dash or climate control when the ENG/MET button is pushed. I now have C13 and C41 in module 1 and ERR on both 4 and 9 even with the ECM disconnected.

Did you disconnect and reconnect the negative battery cable? That should reset everything and should clear the CCM codes.

C13 for Module 1 the CCM indicates a problem with the Driver Information Switches.

You seem to have multiple failures.

Do this check using your voltmeter.
At the Electric Air Pump relay ( the one you jumped).
Disconnect the electrical plug at the relay.
With the Black meter probe connected to the negative battery terminal.
Use the Red meter probe and measure the heavy gauge red wire at the relay connector.
Should measure 12 volts. (hot all the time)

Move the Red meter probe and measure the Pink/Black wire.
With the ignition On you should measure 12 volts.
 

mvsvette

Member
Joined
Mar 7, 2016
Messages
19
Location
Menifee Ca.
Corvette
92 Corvette
Did you disconnect and reconnect the negative battery cable? That should reset everything and should clear the CCM codes.

C13 for Module 1 the CCM indicates a problem with the Driver Information Switches.

You seem to have multiple failures.

Do this check using your voltmeter.
At the Electric Air Pump relay ( the one you jumped).
Disconnect the electrical plug at the relay.
With the Black meter probe connected to the negative battery terminal.
Use the Red meter probe and measure the heavy gauge red wire at the relay connector.
Should measure 12 volts. (hot all the time)

Move the Red meter probe and measure the Pink/Black wire.
With the ignition On you should measure 12 volts.

Update, heavy gage red wire is getting 12 volts. Pink and black not getting 12 volts.
 
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ecss

Well-known member
Joined
Nov 27, 2004
Messages
649
Location
Windsor Mill, MD
Corvette
89 Brilliant Red Metallic
Update, heavy gage red wire is getting 12 volts. Pink and black not getting 12 volts.

No 12 volts on the Pink/Black wire with the ignition On indicates the Air Bag 10 amp fuse in the passenger side end of dash fuse box is probably blown.
 

mvsvette

Member
Joined
Mar 7, 2016
Messages
19
Location
Menifee Ca.
Corvette
92 Corvette
No 12 volts on the Pink/Black wire with the ignition On indicates the Air Bag 10 amp fuse in the passenger side end of dash fuse box is probably blown.

Update, Airbag fuse was blown. I now have the SES light on and 12volts to pink and gray wire at air pump.
 

ecss

Well-known member
Joined
Nov 27, 2004
Messages
649
Location
Windsor Mill, MD
Corvette
89 Brilliant Red Metallic
Update, Airbag fuse was blown. I now have the SES light on and 12volts to pink and gray wire at air pump.

Does the fuel pump prime?
Can you start the car?

If not, if you short A to G can the CCM communicate with the ECM and ABS/ASR?
 

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