MMM codes 01 Eldo

[rockfangd]

Hi all. My memory mirrors on my 01 eldo do not work. I can manually adjust them but they do not set automatically with memory or in reverse.

I pulled 2 codes that are always current and will not clear. I have a feeling it has to do with the fact that I replaced the driver mirror glass because it was broken. To my knowledge the replacement was identical, heated and dimming. I had no issues installing the glass.

I have looked everywhere for the definitions but have found nothing. It doesnt really bother me that the memory part doesnt work but to have it position for paralell parking would be nice.

Codes are as follows

MMM

c1248

c1250

Thanks all

[Logan]

I think the codes are slightly wrong. I do see codes 2148 and 2150 for the mirrors. The mirrors are in the 'doors' section of the DVD service manual. The provided info is for the 2001 Eldo..

DTC B2144, B2146, B2148, or B2150
Circuit Description
The memory mirror module (MMM) receives inputs from the mirror position sensors during the following functions:

• Memory recall

• Memory seat

• Easy exit

The potentiometers in the position sensors vary in resistance as the motors move the mirror. The MMM receives a variable voltage input depending on the resistance of the potentiometer. During memory set, the MMM records the voltages across the mirrors. During memory recall, the MMM moves the mirror motors until the voltage across each potentiometer matches the recorded voltage. During normal operation, the mirror position sensors are checked against out-of-range limits.

Conditions for Running the DTC
DTCs B1982 and B1983 are not set.

Conditions for Setting the DTC
The outside rear view mirrors vertical or horizontal position sensor input voltage is less than 0.25 volts.

Action Taken When the DTC Sets
The memory mirror module (MMM) will disable the affected motor during memory recall.

Conditions for Clearing the DTC
• The memory mirror module (MMM) no longer detects the position sensor failure.

• 50 consecutive ignition cycles have been recorded without the DTC being detected.

Diagnostic Aids
• If DTC B2144 is set by itself, the Left Mirror Vertical Position Sensor Signal circuit may be open or short to ground.

• If DTC B2146 is set by itself, the Left Mirror Horizontal Position Sensor Signal circuit may be open or short to ground.

• If DTC B2148 is set by itself, the Right Mirror Vertical Position Sensor Signal circuit may be open or short to ground.

• If DTC B2150 is set by itself, the Right Mirror Horizontal Position Sensor Signal circuit may be open or short to ground.

• If DTCs B2144 and B2146 were set together, the 5 Volt Reference circuit between splice S225 and the LH outside mirror may be open.

• If DTCs B2148 and B2150 were set together, the 5 Volt Reference circuit between splice S225 and the RH outside mirror may be open.

• If DTCs B2144, B2146, B2148 and B2150 were all set, the following may have occurred:

- The 5 Volt Reference circuit between the MMM and splice S225 may be open.

- the 5 Volt Reference circuit may be short to ground.

Test Description
The numbers below refer to the step numbers on the diagnostic table.

Tests for the proper operation of the circuit in the low voltage range.

Tests for the proper operation of the circuit in the high voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to ground.

Tests for a short to voltage in the 5 volt reference circuit.

Tests for a high resistance or an open in the low reference circuit.

Step
Action
Value(s)
Yes
No

Schematic Reference: Outside Rearview Mirror Schematics

1
Did you perform the Door Systems Diagnostic System Check?
--
Go to Step 2
Go to Diagnostic System Check - Door Systems

2
Install a scan tool.
Turn ON the ignition, with the engine OFF.
With the scan tool, observe the appropriate mirror position parameter in the Memory Mirror Module data list.
Does the scan tool indicate that the mirror position parameter is within the specified range?
0.25 - 4.75 volts
Go to Diagnostic Aids
Go to Step 3

3
Turn OFF the ignition.
Disconnect the appropriate mirror position sensor.
Turn ON the ignition, with the engine OFF.
With a scan tool, observe the mirror position parameter.
Does the scan tool indicate that the mirror position parameter is less than the specified value?
0.25 volts
Go to Step 4
Go to Step 10

4
Turn OFF the ignition.
Connect a 3 amp fused jumper wire between the 5 volt reference circuit of the appropriate mirror position sensor and the signal circuit of the appropriate mirror position sensor.
Turn ON the ignition, with the engine OFF.
With a scan tool, observe the mirror position parameter.
Does the scan tool indicate that the mirror position parameter is greater than the specified value?
4.75 volts
Go to Step 5
Go to Step 8

5
Disconnect the fused jumper wire.
Measure the voltage between the 5 volt reference circuit of the appropriate mirror position sensor and the low reference circuit of the appropriate mirror position sensor.
Does the voltage measure less than the specified value?
4.75 volts
Go to Step 6
Go to Step 7

6
Turn OFF the ignition.
Disconnect the negative battery cable.
Measure the resistance from the low reference circuit of the appropriate mirror position sensor to a good ground.
Does the resistance measure less than the specified value?
5 ohms
Go to Step 12
Go to Step 11

7
Test the 5 volt reference circuit of the appropriate mirror position sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 16
Go to Step 13

8
Test the 5 volt reference circuit of the appropriate mirror position sensor for a short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 16
Go to Step 9

9
Test the signal circuit of the appropriate mirror position sensor for a short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 16
Go to Step 13

10
Test the signal circuit of the appropriate mirror position sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 16
Go to Step 13

11
Disconnect the memory mirror module (MMM).
Test the low reference circuit of the appropriate mirror position sensor for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition?
--
Go to Step 16
Go to Step 13

12
Inspect for poor connections at the harness connector of the appropriate mirror position sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 16
Go to Step 14

13
Inspect for poor connections at the harness connector of the memory mirror module (MMM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?
--
Go to Step 16
Go to Step 15

14
Replace the power mirror motor. Refer to Outside Rearview Mirror Motor Replacement .

Did you complete the replacement?
--
Go to Step 16
--

15
Replace the memory mirror module (MMM). Refer to Memory Mirror Module Replacement .

Did you complete the replacement?
--
Go to Step 16
--

16
Use the scan tool in order to clear the DTCs.
Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
Does the DTC reset?
--
Go to Step 2
System OK

[rockfangd]

Very sorry. It is 2148 and 2150. I nailed what I thought they were except for one thing. It is for the right side. I never touched that one.

Any idea where I should start to look? I see it says something about a splice.

The above post is very helpful. Thank you very much.

[rockfangd]

I think the codes are slightly wrong. I do see codes 2148 and 2150 for the mirrors. The mirrors are in the 'doors' section of the DVD service manual. The provided info is for the 2001 Eldo..

DTC B2144, B2146, B2148, or B2150

Circuit Description

The memory mirror module (MMM) receives inputs from the mirror position sensors during the following functions:

• Memory recall

• Memory seat

• Easy exit

The potentiometers in the position sensors vary in resistance as the motors move the mirror. The MMM receives a variable voltage input depending on the resistance of the potentiometer. During memory set, the MMM records the voltages across the mirrors. During memory recall, the MMM moves the mirror motors until the voltage across each potentiometer matches the recorded voltage. During normal operation, the mirror position sensors are checked against out-of-range limits.

Conditions for Running the DTC

DTCs B1982 and B1983 are not set.

Conditions for Setting the DTC

The outside rear view mirrors vertical or horizontal position sensor input voltage is less than 0.25 volts.

Action Taken When the DTC Sets

The memory mirror module (MMM) will disable the affected motor during memory recall.

Conditions for Clearing the DTC

• The memory mirror module (MMM) no longer detects the position sensor failure.

• 50 consecutive ignition cycles have been recorded without the DTC being detected.

Diagnostic Aids

• If DTC B2144 is set by itself, the Left Mirror Vertical Position Sensor Signal circuit may be open or short to ground.

• If DTC B2146 is set by itself, the Left Mirror Horizontal Position Sensor Signal circuit may be open or short to ground.

• If DTC B2148 is set by itself, the Right Mirror Vertical Position Sensor Signal circuit may be open or short to ground.

• If DTC B2150 is set by itself, the Right Mirror Horizontal Position Sensor Signal circuit may be open or short to ground.

• If DTCs B2144 and B2146 were set together, the 5 Volt Reference circuit between splice S225 and the LH outside mirror may be open.

• If DTCs B2148 and B2150 were set together, the 5 Volt Reference circuit between splice S225 and the RH outside mirror may be open.

• If DTCs B2144, B2146, B2148 and B2150 were all set, the following may have occurred:

- The 5 Volt Reference circuit between the MMM and splice S225 may be open.

- the 5 Volt Reference circuit may be short to ground.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

Tests for the proper operation of the circuit in the low voltage range.

Tests for the proper operation of the circuit in the high voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to ground.

Tests for a short to voltage in the 5 volt reference circuit.

Tests for a high resistance or an open in the low reference circuit.

Step

Action

Value(s)

Yes

No

Schematic Reference: Outside Rearview Mirror Schematics

1

Did you perform the Door Systems Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Door Systems

2

Install a scan tool.

Turn ON the ignition, with the engine OFF.

With the scan tool, observe the appropriate mirror position parameter in the Memory Mirror Module data list.

Does the scan tool indicate that the mirror position parameter is within the specified range?

0.25 - 4.75 volts

Go to Diagnostic Aids

Go to Step 3

3

Turn OFF the ignition.

Disconnect the appropriate mirror position sensor.

Turn ON the ignition, with the engine OFF.

With a scan tool, observe the mirror position parameter.

Does the scan tool indicate that the mirror position parameter is less than the specified value?

0.25 volts

Go to Step 4

Go to Step 10

4

Turn OFF the ignition.

Connect a 3 amp fused jumper wire between the 5 volt reference circuit of the appropriate mirror position sensor and the signal circuit of the appropriate mirror position sensor.

Turn ON the ignition, with the engine OFF.

With a scan tool, observe the mirror position parameter.

Does the scan tool indicate that the mirror position parameter is greater than the specified value?

4.75 volts

Go to Step 5

Go to Step 8

5

Disconnect the fused jumper wire.

Measure the voltage between the 5 volt reference circuit of the appropriate mirror position sensor and the low reference circuit of the appropriate mirror position sensor.

Does the voltage measure less than the specified value?

4.75 volts

Go to Step 6

Go to Step 7

6

Turn OFF the ignition.

Disconnect the negative battery cable.

Measure the resistance from the low reference circuit of the appropriate mirror position sensor to a good ground.

Does the resistance measure less than the specified value?

5 ohms

Go to Step 12

Go to Step 11

7

Test the 5 volt reference circuit of the appropriate mirror position sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 13

8

Test the 5 volt reference circuit of the appropriate mirror position sensor for a short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 9

9

Test the signal circuit of the appropriate mirror position sensor for a short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 13

10

Test the signal circuit of the appropriate mirror position sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 13

11

Disconnect the memory mirror module (MMM).

Test the low reference circuit of the appropriate mirror position sensor for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 13

12

Inspect for poor connections at the harness connector of the appropriate mirror position sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 14

13

Inspect for poor connections at the harness connector of the memory mirror module (MMM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 15

14

Replace the power mirror motor. Refer to Outside Rearview Mirror Motor Replacement .

Did you complete the replacement?

--

Go to Step 16

--

15

Replace the memory mirror module (MMM). Refer to Memory Mirror Module Replacement .

Did you complete the replacement?

--

Go to Step 16

--

16

Use the scan tool in order to clear the DTCs.

Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK

Thanks for your great response. Thanks to your help I have found the cause. Someone replaced the passenger side mirror assembly with a non memory unit and it does not have the 4 pin plug it needs.

I dont know how long it will take to find one but I hope to eventually get one.

[rockfangd]

Well thanks to your help I now have memory mirrors again.

I managed to find a mirror from a 1997 Eldo.

They work great and I love the paralell park mode.

Now I see the eldo had the option along with the MSM but I dont think the Seville did in 97. My 97 Seville has MSM but I dont think MMM.

And I dont think the Deville does either til 2000. Can someone enlighten me on the years in which the feature was available.

[Cadillac Jim]

I have the 1997 FSM for Eldroado, Seville, and Deville, and there is a section for Deville memory mirrors, and a section for the Seville/Eldorado. So all three models had memory mirrors for 1997. I believe that they were standard for the STS/ETC.

[rockfangd]

Ok.

I assumed that if it was equipped with the memory option that it would have had the mirrors too.

But I am pretty sure my 97 Seville does not have MMM although it does have the memory seating and options

[rockfangd]

Ok I kind of feel like an idiot. The feature is there on my 97 Seville.

I dont think it works quite the same though.

If you read the owners manual it is not very specific on much of anything on memory mirrors.

It does work though I tried it tonight, there is no settings to change for them though like the 01 eldo.

It must be the curbview did not come about til around 99-2000

[Cadillac Jim]

You can tell by running the OBD codes and watching for the MMM module. It's the last one, and follows the MSM module.

[rockfangd]

it is there and has no codes.

I probably never noticed because nobody but me has driven the car, and I rarely ever use the 2 remote