1998-99 PCM Connector Pin Out Charts
(GM 4.3L, 5.0L, 5.7L)

PCM Connector: Blue (C1) 1998-99

1998-1999 Blue PCM Connector Pinout

In this article, you'll find the Pin Out descriptions of the 4 PCM Connectors for the 1998-1999 GM 4.3L, 5.0L or 5.7L Engines.

NOTE: For other PCM pin-out charts, take a look at the following:

  1. 1993 PCM Pin Out Chart (GM 4.3L, 5.0L, 5.7L GAS w/ 4L60-E).
  2. 1994 PCM Pin Out Chart (GM 4.3L, 5.0L, 5.7L GAS with A/T).
  3. 1995 PCM Pin Out Chart (GM 4.3L, 5.0L, 5.7L GAS with A/T).
  4. 1996-97 PCM Connector Pin Out Charts (GM 4.3L, 5.0L, 5.7L).

Each connector can be identified as:

  1. C1 Blue (32 Pin Connector).
  2. C2 Red (32 Pin Connector).
  3. C3 Clear -or Grey- (32 Pin Connector).
  4. C4 Black (24 Pin Connector).

In trying to keep everything organized, you'll find one PCM connector pin out chart in each of the 4 pages that make up this article:

  1. C1 Blue.
  2. C2 Red .
  3. C3 Clear -or Grey- .
  4. C4 Black .

The symbol: <-> means that the Connector Pin # will have one of two different wires DEPENDING on the actual year of your vehicle or whether your it's equipped with a 4.3L, 5.0L, 5.7L, etc.

C1 (Blue) PCM 32 Pin Connector
Pin Wire Color Description
1---Empty
2---Empty
3Brown w/ White stripe1X Cam (CMP) Sensor Signal
4---Empty
5---Empty
6---Empty
7TanHO2S Low Bank 2 Sensor 1
8Pink w/ Black stripeCam (CMP) Sensor Ground (Low)
9PurpleFuel Gauge (Fuel Level Output)
10 <->---Empty (1998 Only)
10 <->Tan w/ Black stripeTCC Control Solenoid (1999 Only)
11---Empty
12---Empty
13---Empty
14BrownAIR Relay Control (California Only)
15Yellow w/ Black stripeVehicle Speed Sensor (VSS)
16---Empty
17---Empty
18 <->Purple w/ White stripeDual Tank Fuel Module (1998 Only)
18 <->---Empty (1999 Only)
19Purple w/ White stripeHO2S High Bank 1 Sensor 1
20 <->PurpleHO2S High Bank 1 Sensor 2 (1998 Only)
20 <->PurpleHO2S High Bank 2 Sensor 2 w/out C6P -under 8600 GVW (1999 Only)
20 <->PurpleHO2S High Bank 1 Sensor 2 w C6P -over 8600 GVW (1999 Only)
21PurpleHO2S High Bank 2 Sensor 1
22 <->Purple w/ White stripeHO2S High Bank 2 Sensor 2 (1998 Only)
22 <->Purple w/ White stripeHO2S High Bank 2 Sensor 2 w/ C6P -over 8600 GVW (1999 Only)
22 <->Purple w/ White stripeHO2S High Bank 1 Sensor 2 w C6P -under 8600 GVW (1999 Only)
23---Empty
24 <->TanHO2S Low Bank 1 Sensor 2 (1998 Only)
24 <->TanHO2S Low Bank 2 Sensor 2 w/out C6P -under 8600 GVW (1999 Only)
24 <->TanHO2S Low Bank 1 Sensor 2 w/ C6P -over 8600 GVW (1999 Only)
25Tan w/ White stripeHO2S Low Bank 1 Sensor 1
26 <->Tan w/ White stripeHO2S Low Bank 2 Sensor 2 (1998 Only)
26 <->Tan w/ White stripeHO2S Low Bank 2 Sensor 2 w/ C6P -over 8600 GVW (1999 Only)
26 <->Tan w/ White stripeHO2S Low Bank 1 Sensor 2 w/out C6P -under 8600 GVW (1999 Only)
27---Empty
28PurpleCrank (CKP) Sensor Ground (Low)
29Light Green w/ BlackVehicle Speed Sensor (VSS) Low
30Purple w/ White stripeVehicle Speed Sensor (VSS) Signal
31Yellow4X Crank (CKP) Sensor Signal
32---Empty

Safety Precautions

Here are some very important safety precautions when testing the wires coming out of the PCM connectors.

  1. If one or any of the wires on your GM vehicle DO NOT match the color stated in the Pin Out Charts... then you should not use the Pin Out charts in this article. Why? Because this is the clearest indication that these ARE NOT the Connector Pin Out Charts for your particular vehicle.
  2. Never probe the front of the Connector.
    1. You should use a Wire Piercing Probe and probe the wire a few inches away from the connector.
      1. To see what this tool looks like: Wire Piercing Probe.
    2. You should use a Back Probe.
  3. You should never disconnect any of the PCM connectors without first disconnecting the battery negative terminal.
  4. This is a FLASH unit and requires reprogramming if replaced with a new one or used one.

Disclaimer

I've spent many an hour double, triple, and quadruple checking these pin out charts (in these page and in the next couple of pages) using the best sources to compile it... but nothing in life is perfect. I don't have a staff of proof readers or editors (or even volunteers)... I'm just a little guy typing this stuff up in my spare time to help and give back to the Do-It-Yourself community. So without further ado, here's my disclaimer:

© copyright Abraham Torres-Arredondo: This information is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

If you do spot errors, please let me know. You can use the contact form at the end of the article.

PCM Connector Pinouts

Cadillac Vehicles:

  • Escalade
    • 1999

Chevrolet Vehicles:

  • Astro 4.3L
    • 1998, 1999
  • Blazer
    • 1998
  • C1500, C2500, C3500 Pick Up
    • 1998,1999

Chevrolet Vehicles:

  • Express Van 1500, 2500, 3500
    • 1998, 1999
  • K1500, K2500, K3500 Pick Up
    • 1998, 1999
  • K1500, K2500 Suburban
    • 1998, 1999
  • P30 Van
    • 1998
  • S10 Blazer
    • 1998

Chevrolet Vehicles:

  • S10 Pick Up
    • 1998
  • Silverado 1500 Pick Up
    • 1998, 1999
  • Tahoe
    • 1998

GMC Vehicles:

  • Sierra C1500, C2500, C3500
    • 1998, 1999

GMC Vehicles:

  • Suburban C1500, C2500
    • 1998, 1999
  • G3500 Van & Vandura
    • 1998
  • Jimmy & Envoy
    • 1998
  • K1500, K2500, K3500 Sierra
    • 1998, 1999
  • P3500 Van
    • 1998

GMC Vehicles:

  • Safari
    • 1998, 1999
  • Savana Van 1500, 2500, 3500
    • 1998, 1999
  • Sonoma
    • 1998
  • Yukon
    • 1998

Oldsmobile Vehicles:

  • Bravada
    • 1998

Isuzu Vehicles:

  • Hombre
    • 1998

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Robin Williams

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