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For 1990-2009 cars only

DTC P1811 Maximum Adapt and Long Shift 6.5L Diesel only

Table 1: 4L80-E Range Reference, modified for DTCs P1870 & P1871
Table 2: DTC P1811 Maximum Adapt and Long Shift (6.5L Diesel Only)

4L80-E Range Reference, modified for DTCs P1870 & P1871

Range

Gear

1-2 Sol

2-3 Sol

Fourth Clutch

Overrun Clutch

O/D Roller Clutch

FWD Clutch

Direct Clutch

Front Band

Interm. Sprag Clutch

Interm Clutch

Lo Roller Clutch

Rear Band

Overdrive

1st

On

Off

--

--

H

A

--

--

*

--

H

--

2nd

Off

Off

--

--

H

A

--

--

H

A

O

--

3rd

Off

On

--

--

H

A

A

--

O

A

O

--

4th

On

On

A

--

O

A

A

--

O

A

O

--

  • A = Applied
  • H = Holding
  • * = Holding but not effective
  • O = Overrunning

Circuit Description

The PCM compares the measured gear ratio to the known actual value. This allows the PCM to determine the actual gear range of the transmission. When an upshift is commanded, the PCM measures the interval during which the gear ratio leaves the current range and changes to reflect the commanded upshift. This interval is expressed on the scan tool as Shift Time. When this interval has exceeded a predetermined limit, the PCM utilizes the shift adapts in order to attempt to shorten the shift time.

If the PCM detects when the maximum allowable shift time has been exceeded and the upshift adapts have reached their upper limit, then DTC P1811 sets. DTC P1811 is a type D DTC.

Conditions for Setting the DTC

    • The engine must be running for greater than 5 seconds.
    • The 1-2 and the 2-3 upshifts are greater than 1.25 seconds.
    • The 3-4 upshifts are greater than 6.38 seconds.
    • The above conditions exist for 5 consecutive upshifts.

Action Taken When the DTC Sets

    • The PCM commands maximum line pressure.
    • DTC P1811 is stored in memory.

Conditions for Clearing the MIL/DTC

    • The PCM turns OFF the MIL after three consecutive ignition cycles without a failure reported.
    • A scan tool can clear the DTC from the PCM history. The PCM clears the DTC from the PCM history if the vehicle completes 40 warm-up cycles without a failure reported.
    • The PCM cancels the DTC default actions when the fault no longer exists and the ignition is OFF long enough in order to power down the PCM.

Diagnostic Aids

    • Inspect the wiring for poor electrical connections at the PCM. Inspect the wiring for poor electrical connections at the transmission 20-way connector. Look for the following conditions:
       - A bent terminal
       - A backed out terminal
       - A damaged terminal
       - Poor terminal tension
       - A chafed wire
       - A broken wire inside the insulation
    • When diagnosing for an intermittent short or open condition, massage the wiring harness while watching the test equipment for a change.
    • DTC P1811 can be caused by a faulty turbocharger or wastegate assembly. If no other symptoms are present, check the turbocharger system for proper operation.
    • While driving the vehicle, inspect for loss of power, misfire, or other engine related driveability conditions.

Test Description

  1. This step tests for low fluid level, which can cause delayed shifts.

  2. This step compares the indicated range signal from the Range Signal table to the Automatic Transmission Fluid Pressure Manual Valve Position Switch (TFP Val. Position Sw.) selected gear range.

  3. This step tests for low line pressure, which can cause delayed and long shifts.

DTC P1811 Maximum Adapt and Long Shift (6.5L Diesel Only)

Step

Action

Value(s)

Yes

No

1

Was the Powertrain On-Board Diagnostic (OBD) System Check performed?

--

Go to Step 2

Go to OBD Powertrain System Check

2

Have you performed the transmission fluid checking procedure?

--

Go to Step 3

Go to Transmission Fluid Check

3

  1. Install the scan tool (tech 1) ®.
  2. With the engine OFF, turn the ignition switch to the RUN position.
  3. Important: Before clearing the DTCs, use the scan tool in order to record the Freeze Frame and Failure Records for reference. The Clear Info function will erase the data.

  4. Turn the ignition switch to the Run position.
  5. Record the DTC Freeze Frame, Failure Records and DTCs. Use the scan tool snapshot mode in order to record the shift times.
  6. Important: If any other engine or transmission DTCs are set, refer to their respective diagnostic tables first.

  7. Select TFP Sw. A/B/C on the scan tool.
  8. Start the engine and apply the brake pedal.
  9. Select each gear range: D1, D2, D3, D4, N, R, and P.

Does each selected transmission range match the TFP Sw. A/B/C display on the scan tool? (Refer to the Range Signal table.)

--

Go to Step 4

Go to DTC P1810 Pressure Switch Assembly Malfunction

4

  1. Drive the vehicle in D4 in order to obtain a 1-2, a 2-3, and a 3-4 shift time.
  2. Use the scan tool snapshot if the gear ratio reads out of range in 1st, 2nd, or 3rd gear.

Were all of the shift times above the specified value? (Refer to the Shift Solenoid Valve State and Gear Ratio table.)

1-2 or 2-3 upshifts: 1.25 seconds

3-4 upshifts: 6.38 seconds.

Go to Step 5

Go to Step 8

5

Perform the line pressure test.

Refer to Line Pressure Check .

Is the line pressure within specifications?

--

Go to Step 6

Go to Symptom Diagnosis table, Low Line Pressure

6

  1. Remove the transmission oil pan.
  2. Refer to Changing the Fluid and Filter, in On-Vehicle Service.

  3. Inspect the pan and the fluid for contamination.

Is there excessive contamination in the transmission oil pan?

--

Go to Transmission Overhaul , in Unit Repair

Go to Step 7

7

Inspect the transmission for fluid pressure loss in the following areas:

    • Valve Body Gasket
    • Forward Clutch Seals
    • Turbine Shaft Seals

Refer to Transmission Overhaul , in Unit Repair.

Did you find and correct a condition?

--

Go to Step 15

--

8

Inspect the 1-2, 2-3, and the 3-4 adapt cells on the scan tool.

Were any of the upshift adapt cells at their maximum adapt limit?

--

Go to Step 9

Go to Diagnostic Aids

9

Did the 3-4 shift time exceed the specified value?

6.38 seconds

Go to Step 12

Go to Step 10

10

Did the 2-3 shift time exceed the specified value?

1.25 seconds

Go to Step 13

Go to Step 11

11

Did the 1-2 shift time exceed the specified value?

1.25 seconds

Go to Step 14

--

12

Inspect the following 3-4 shift circuit components:

    • 4th Gear Clutch Plates
    • 4th Gear Clutch Seals

Refer to Transmission Overhaul , in Unit Repair.

Did you find and correct a condition?

--

Go to Step 15

--

13

Inspect the following 2-3 shift circuit components:

    • Turbine Shaft Seals
    • Forward Clutch Plates
    • Forward Clutch Seals
    • Direct Clutch Plates
    • Direct Clutch Seals
    • Center Support Seals
    • Improperly tightened Center Support Bolt

Refer to Transmission Overhaul , in Unit Repair.

Did you find and correct a condition?

--

Go to Step 15

--

14

Inspect the following 1-2 shift circuit components:

    • Low Roller Clutch
    • Intermediate Clutch Plates
    • Intermediate Clutch Seals
    • Intermediate Sprag Clutch
    • Overdrive Roller Clutch
    • Improperly tightened Center Support Bolt

Refer to Transmission Overhaul , in Unit Repair.

Did you find and correct a condition?

--

Go to Step 15

--

15

In order to verify your repair, perform the following procedure:

  1. Select DTC.
  2. Select Clear Info.
  3. Turn the ignition key to the Run position.
  4. Review the scan tool DTC Info.
  5. Select Specific DTC. Enter DTC P1811.

Has the test run and passed?

--

System OK

Begin diagnostic again. Go to Step 1