Bulletin No.: PIT5593B
Published date: 05/28/2020

Preliminary Information
PIT5593B Action Required Steering Assist is Reduced Drive with
Care Or Service Power Steering Message And Or Current Power
Steering Control Module DTCs
Product Investigation Review Required
Models
Brand:

Model:

VIN:

Model
Years: from

Engine:

to

Transmissions:

Silverado
Chevrolet
1500

2017 SOP
2018

Plant Code Z*: 9/12/2017, Plant
Code F*: 9/13/2017, Plant Code G*:
9/15/2017

4.3L RPO LV3 / 5.3L
RPO L83 / 6.2L RPO
L86

All

Chevrolet Suburban

2017 SOP
2018

Plant Code R*: 9/12/2017

All

All

Chevrolet Tahoe

2017 SOP
2018

Plant Code R*: 9/12/2017

All

All

GMC

Sierra
1500

2017 SOP
2018

Plant Code Z*: 9/12/2017, Plant
Code F*: 9/13/2017, Plant Code G*:
9/15/2017

4.3L RPO LV3 / 5.3L
RPO L83 / 6.2L RPO
L86

All

GMC

Yukon

2017 SOP
2018

Plant Code R*: 9/12/2017

All

All

*For Plant Code See 11th Position of VIN
Involved Region or Country North America
Additional Options (RPO)

Without RPO UHX Lane Keep Assist
Without RPO NV8 Variable Assist Power Steering
Note: This PI does NOT apply to 2500/3500 HD Trucks.

Condition

Some customers may comment every time the vehicle is started an "Action
Required Steering Assist is Reduced Drive with Care" Or "Service Power Steering"
Message is displayed. In most cases, there will be no steering related issues and if
the message is dismissed it will remain o the entire ignition cycle.
When checking for DTC's the Power Steering Control Module (PSCM) will have
current DTC's set. The most common DTC's which may set are C0176, C0544,
U0100, U0101, U0140, U0121, U0073, U0126, U0428 71, U0415 and/or U0401.

Cause

A PSCM calibration error has been found, which does not allow its DTC's to
transition to history and they stay current. Even when the issue that caused the
DTC's to set originally, is no longer present, the PSCM will retain the DTC(s) as
current.

Correction:
This calibration error can mislead technicians, because the initial steps in normal strategy based diagnosis is to
verify the customer complaint and follow current DTC's. To help avoid misdiagnosis, follow the steps below:

1. Check and record all DTC's in all modules.
2. Clear all DTC's. If all DTC's can be cleared, go to step 3. If DTC's will not clear, the vehicle is experiencing a
current fault, which will need to be diagnosed and repaired before continuing to step 3.
3. Reprogram the PSCM with the latest calibrations currently available in TIS2WEB, and clear any DTC's which may
have set during the programming event.
4. Let the vehicle go to sleep, then restart the engine and check for DTC's. If any DTC's reset, perform normal
diagnosis and repair as necessary.
5. If no DTC's reset, it will be necessary to look at all recorded DTC's in step 1 to help determine the original root
cause. See additional information/example below.
Additional Information and Example
Remember, this PSCM calibration error only causes the DTC's to stay current, which then causes the PSCM
messages to appear at each start up. After reprogramming the PSCM with the latest calibrations, the original root
cause of the DTC's may still need to be addressed. See example below.
- Customer brings the vehicle in for an "Action Required Steering Assist is Reduced Drive with Care" message that
is displayed each ignition cycle. See DIC message below.

- When checking for DTC's the following codes are found: See also the GDS2 screen print of the DTC's below.
PSCM has two current DTC's U0415 and U0401
EBCM has two history DTC's C0035 and C0045

- When performing normal strategy based diagnosis, a technician would start the vehicle and verify the
customer's complaint of the "Action Required Steering Assist is Reduced Drive with Care" message, he or she
would nd current DTC's set in the PSCM. Finding these current codes may lead a technician down the wrong
path, which is why it is important to follow the steps listed above.
- In this example, all the DTC's cleared out and the PSCM was reprogrammed with the latest calibrations available
in TIS2WEB.
- Looking back at all the DTC's recorded, the EBCM had two wheel speed sensor DTC's set: C0035 and C0040.
These two DTC's would be the original root cause and would need to be addressed.
- If the vehicle was returned to the customer without addressing the EBCM DTC's, he or she may return for service
but would be a di erent complaint, such as, an intermittent ABS MIL and/or Service Stabilitrak message. The
same DTC's will be found in the PSCM and EBCM, but now the new PSCM calibration will allow the DTC's
to transition to history and there will no longer be a PSCM DIC message displayed at each ignition cycle.

Warranty Information
For vehicles repaired under the Bumper-to-Bumper coverage (Canada Base Warranty coverage), use the
following labor operation. Reference the Applicable Warranties section of Investigate Vehicle History (IVH) for
coverage information.
Labor Operation
2810625

Description
Labor Time
Power Steering Control Module Reprogramming with
Use Published Time
SPS

Additional SI Keywords
C0176 C0475 c0544 c0545 C056D C0045 C0050 U0100 U0101 U0140 U0121 U0126 U0131

Version History
Version

Modi ed

3
Created on 11/06/2017
04/23/2018 - Update the engines in the model list, add a Note in the
Condition to Excluded HD trucks, and update the Additional Options to
add Without RPO NV8 Variable Assist Power Steering
05/21/20 - Updated to include additional DTC's C0176, C0544, U0100, U0101,
U0140, U0121, U0073, U0126, U0428 71

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